I've heard of this happening to some Oilheads but it did not deter me from buying a second hand 1150GS less than 2 months ago.
If you check the ADV Riders site, you'll also find mention of a 300,000km 1100GS. Another guy by the name of jkam covered most of the world on one.
I'd say that only bad points are the complexity of the injection system. When it comes to servicing, it is absolutely no different to an Airhead. It is a 4v head but still screw & locknut tappets. All of the oil & filter changes are as per the Airhead with the exception of the Oilheads fuel filter. This can be a PITA but only needs changing every 24,000 miles although I'd change every 12,00o if using dirty fuel from a drum. You can easily fit an external fuel filter if you're concerned.
I bought a non-ABS model, partly because of cost but mainly because of complexity & the fact that read many reports of it going wrong.
I carried out the Throttle Body Synch yesterday, very easy with the correct eqp't (Carbtune 2 in my case) & some instructions.
I'd say the only other downside is that they're about 30kg heavier than an R80GS Paralever, which makes them a little more difficult on steep, narrow slopes (i.e. me at the recent UK meet's off road ride out - see photo, lol).
On the other hand, they make excellent road bikes. Even after 13 years on GSX-R1100's, I'm still happy with mine. They stop & steer well & can be really leant over, even on Tourances's, without losing grip.
The Adventure model has 20mm longer suspension (not for the short of leg), a non-adjustable single seat & comes with a 30 litre tank & braided brake lines as standard.
Seats on neither model are that comfortable IMO but there are many options from cheap to expensive. If planning a serious trip, money spent on uprated suspension would be the first thing I'd do.
One final point, in the UK at least, the introduction of the new 1200 has caused many people to sell their 1150GS, leading to a drop in second hand prices & a slightly flooded buyers market - worth checking out if considering a used bike. Prices of Adventure models are still quite high as they're still available new.
[This message has been edited by Steve Pickford (edited 19 July 2004).]