Well my 10p worth,
1) it would depend on your riding & where your going i.e. if all road tarmac it don't really matter of soft or hard box's, just bear in mind the speed your riding & & loss of fuel over the wait by the distance & drag factor. (not much i suppose really),
if going on some of the more adventures roads (dirt track etc) I would suggest you look @ the Ali box's full stop. they will help protect your gear & possibly the bike's wheels. I find it strange they can fall apart that easy!!
I know on the GS forum there is a guy who makes his own £300 loads of guys buy them from him as they are really good, (no i have not got any),
as for the panniers frames look @ Motohaus Powersports Limited S W Motech Side Carriers, Alu Racks and Boxes

I honestly think the only reason 90% of ppl riding any bike have used the Ali style box's because a certain 2 ppl used them good free publicity. If KTM had gave them the bikes would every one be bimbling about on ktm's probably.

Overall look at style of riding & where your going/distance, look at the amount of gear you will need/want to take.

btw I have used both & found the soft option ok for going a way for a few days or quick bit of shopping, the ali for more distance

only my 10p worth

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We are the Pilgrims, Master, we shall go Always a little further: it may be beyond that last blue mountain barred with snow, Across that angry or that glimmering sea.

I would like to suggest another option. When we did our UK to Cape Town trip - my wife and I on a 1989 R100GS we needed decent luggage capacity for as my wife puts it 'living on the bike for a year'. I knocked up plywood panniers and some fairly heavy duty frames (20mm square section tube) which used the existing mounting points. In the whole design there is no attempt to save weight which may be the only downside. Everything you see on the bike i.e. panniers + contents and frames, all the other bags including tank bag, water carriers (empty) and the front rack weighed in at 91kg just after this photo was taken on our return to Devon, which I don't think is too bad for 2 people. The bike was a bit of a handful in the desert and the panniers were mounted a little low and tended to dig in on twisty tarmac roads. After a number of hard falls in the Kalahari we did manage to cause some slight damage to one pannier but this was easily fixed after a quick visit to a hardware shop in Ghanzi for a few wood screws.





It appears I unwittingly incorporated some interesting features not seen on other hard luggage:

• Panniers are side opening. Lid is about 2/3 of the pannier height and folds down to make a shelf ideal for making a roadside brew! The bottom part of the pannier was used to store stuff we didn't need everyday. Waterproofing was not a problem although we never completely submerged them.
• The panniers lift off the frames and make ideal camping seats. The black bar around the top is hinged and padlocked at the back to hold the pannier to the bike and the lid closed.
• The frames pick up on the standard fixing points and are braced across the back as well and I believe this added strength to the rear subframe. I know the paralever subframe is better than the monolever but with rider and passenger totalling 150kg and 90kg of luggage it needed all the help it could get

If we have the opportunity to do another overland trip I would try to make up an improved system in aluminium with at least some attempt to keep the weight down. Definately be on the same bike.