Hi,

Can't comment personally on either performance or reliability as I haven't owned any kind of gps yet.

However, reading the reviews online it seems that all the GPS recievers that use the new SiRF low power chipset have very good performance in terms of TTFF, number of fixes, sensitivity, accuracy and power consumption. From what I have read so far, they seem to meet (or sometimes exceed) the performance of normal handheld GPS in all except battery life, although the Royaltek is good with 10.5 hours continuous (can be extended by ~30% by using low power mode available with the latest v2.3 firmware). Thats better than many handhelds.

As these are solid state devices there are no mechanical parts to break, except the solder joints and circuits, I think reliability will come down to waterproofing (easily achieved with a bag), and vibration / shock proofing. If the receiver is placed in a backpack or pocket, there will be no problems with vibration but you'd be running on batteries so when on the bike it would be preferable to have it mounted and plugged in to power. For this, I think a vibration proof mount is the way to go. I think most of the robustness concern should be focused on the PDA. Mountain bikers are using these PDA / Bluetooth GPS receiver combinations and I reckon a mountain bike gives some fairy serious shocks through the bars, especially when you consider the relative lack of suspension they have. These devices are all pretty new to the market so I don't think any real world long term reliability info is going to be available for a while. The reviews and feedback so far seem promising though.

My *personal* view on the handheld vs PDA / bluetooth situation as it stands now is:

Traditional Handheld Pro:
>Single compact unit, relatively cheap.
>Availability of extra 'nice' features like barometers & digital compasses although nothing that can't be obtained in a watch if you want it...at extra expense.
>Quite good battery life (Excellent on the Silva) - Only matters when away from the bike.
> Most seem to have good track logging features which seems very useful if you get lost!
>Trusted global suppliers e.g. Garmin, Magellan, Silva etc
>Well tried and tested in extreme environments some seem more robust and reliable than others but there are lots of opinions and evidence available to make a safe choice.

Traditional Handheld Con:
> Poor screen (compared to new PDA's)
> Lack of topo maps.
> Restricted to the manufacturer to supply digital maps plus you have to buy paper maps too anyway. Not a problem for street maps but useless for topo.
> Paper maps cannot be scanned and downloaded to GPS.
> Software doesn't come with PDA version meaning you need access to a laptop to download maps / plan & manage routes / waypoints or use alternative software like OziExplorer but that can't read the digital maps supplied by the handheld manufacturers because of commercial licensing.
> Limited support for waypoint / route / track management and storage (although the Magellan has a CF card slot that solves this.

PDA / Bluetooth Pro:
> Superior screen
> Plenty of storage capacity for routes & maps etc if you get a model that has a CF card slot, or one of the equivalents like SD card or sony memory stick.
> Software like Ozi enables you to plan routes and navigate entirely on the PDA using scanned paper maps. No laptop necessary, no downloading to GPS necessary.
> Can either use bought digital maps or scanned paper maps, not tied to a single supplier.
> Routes / waypoints / tracks etc can be uploaded to the internet via bluetooth or cable to mobile phone for extra backup.
> PDA / mobile has many other uses e.g. journal, contacts, tracking finances, email & web access when away from internet cafes.
> Relatively cheap way to get GPS if you are going to buy a PDA anyway.

PDA / Bluetooth Con:
> Expensive if you are not going to get a PDA anyway.
> Two separate devices to mount / carry / lose. Both devices must be operational to navigate.
> Fragility of devices unknown although there seem to be many solutions to this like otterboxes, waterproof bags, vibration proof mounts. These actually achieve greater protection than offered by many handhelds. Also, the reports from mountain bike users on robustness is promising but thin on the ground.
> Need to buy extra software like Ozi for mapping, but this is cheap-ish.
> Battery life (only matters away from bike) - The GPS recievers are ok (Earthmate, RoyalTek) but the PDA's are not so good especially with bluetooth permanently switched on.
> PDA must be always on to record tracks (see battery life!) UNLESS you go for a receiver with built in datalogger like the RoyalTek or Deluo BlackBox GPS. I emailed Delorme to ask if they intend to put a datalogger in the Earthmate but have had no response as yet. The Earthmate has a really nice flexible battery arrangement but without a datalogger you would be limited by the PDA battery life when away from the bike.

Summary, all just my opinion of course, comments welcome!:

>If you just want reliable location and direction and aren't interested in digital topo maps buy a non-mapping handheld...duh.
>If you want street mapping / navigation and don't mind being tied to a single map supplier buy a handheld.
>If you are not prepared to take a chance on new technology, buy a handheld. Personally though I think new handhelds are just as likely to suffer gremlins as any other technology. Don't rely on technology, buy a compass and paper maps is the advice from most experienced people I have spoken to.
>If you dont like being tied to a single map supplier, go for a PDA solution.
>If you don't want to buy digital maps in addition to paper maps, go for a PDA solution - no good for street auto routing though, you have to buy proper street mapping PDA software for that.
>If you want digital topo mapping and extended planning and management capabilities, go for the PDA solution.

If you want to minimise your need to be near a laptop or internet cafe, go for a PDA solution.

Incidentally, I ruled out:
>GPS mouse - needs power, no good when away from bike..very cheap though.
>CF card GPS / GPS sleeve - drastic effect on PDA battery life and PDA would need to be on constantly to record tracks. Uses up CF slot and swapping in and out with memory cards increases chance of failure.

My personal best of breed solution (today) is:

PDA:
HP iPaq 2210. CF and SD card slots, fast, good screen, bluetooth built in, small and light. Not bad battery life. Will probably use an IBM microdrive in the CF slot for 1Gb of storage.

GPS:
Royaltek RBT3000/ Deluo BlackBox / Delorme Earthmate (but only if they add a datalogger). Bluetooth for wireless hiking, datalogger essential to conserve PDA batteries when away from bike while still maintaining track logging.

Software:
Ozi Explorer (CE) good software, good price, powerful waypoint / route planning and management. Use scanned paper maps. Lots of nice little addons like a program that will take a Ozi track log and link it to the information stored in images from most digital cameras so that my pictures are 'located'.

Protection:
Waterproof PDA wallet (Aquapac?), plus shock / vibration proof mountian bike mount that I will 'customise' to add extra crash padding for the PDA. When off the bike, the PDA will be round my neck on a lanyard so extra padding is unnecessary but it will still be in the waterproof wallet. I considered the Otterbox but it is just too big for my liking, ok on the bike but a pain off it.

Battery life:
This little beauty I found today so you can recharge any low power electronic device using elbow power in an emergency:
http://www.gpspassion.com/fr/articles.asp?id=65&page=4

Maps:
Scanned paper maps. Might consider some autorouting PDA software for Europe, North America and Australia but probably not as I'd rather have the cash in my pocket and ask directions when lost.

This selection is based around my plan which is that I intend to scan my paper maps and download them to the PDA, should fit quite a lot onto a 1Gb microdrive. Additional map scanning and downloading to PDA while on the road will be done at internet cafes or friendly souls that don't mind me using their computer. Plan my routes at home on my laptop, and on the road on the PDA using OziExplorer / OziCE. Upload tracklogs from GPS datalogger to PDA and save all of them so I have a *complete* record of my trip. Keep journal etc on PDA. Backup all PDA data via internet either in internet cafe or via bluetooth to mobile phone (Sony - Ericsson T68i). Use PDA for email and web access when away from cafe's, including updating of weblog from journal entries. Get a mate at home to archive all data to CD for me. When I get back, link all my pictures / sound clips / video clips / journal entries / GPS tracks together to make a complete trip log. Use PDA as mp3 player when I miss my CD collection & hi-fi sooo much ;-) I think this gives me the navigation and level of record keeping I want with the minimum of time & hassle spent doing it, hence more time for and chatting. My main concern is reliance on fragile electronics but that also applies to traditional handheld GPS's and as everyone says 'learn to use a map and compass'. I'm going to wait a bit longer before taking the plunge with this stuff as it fairly new to market and I expect prices to drop...unless there is a nice sponsor out there who would like me to test it all for them ;-) Also I wouldn't mind reading a few more reviews and tests before parting with my own cash. I'll keep posting what I learn here.

Excellent sites for info, news and reviews:
www.pocketgps.co.uk
www.gpspassion.com

Phew, I hope someone can be bothered to read all that! Do I win a prize for the longest ever post on HU?

Take it easy, Andy.