I have the Superduke 990 which uses a tuned up version of that engine, water pump seal can go at 10-20k miles which then allows water into the oil but it's not a big deal to sort if you're handy with the spanners. They are also a thirsty engine but have plenty of poke. No idea about the bike in general as I haven't had one.
A friend in Ireland has one. We spend a week touring together each year - usually Scotland - he on his 990, me on my BMW R1150GS. While my GS is the better road bike being able to maintain a higher cruising speed, his is far more agile in narrow, twisty roads having more power and being lighter. I've just asked him what problems he's had and he said he's only needed to replace the clutch cylinder with an aftermarket one (common problem), fit new head race bearings and a battery (probably due to being unused during the winter - he now uses an Optimate). The screen isn't adjustable like the BMW and he did find turbulence buffeting his head a problem so fitted an aftermarket deflector to his screen top which improved things. Other than that he's a very happy owner.
Had my 990 adv for few years now. Had the 950 before that.
Both have been great reliable bikes. Been across the Pyrenees and the alps both on and off road. Personally found the 950 easier to control off road than the 990 due to the 950 being carbs. However, have replaced the throttle cam on the 990 which has improved throttle control at off road type slow speed. Loads of power and as said before they are great on the twisties, a brave rider (not me) will give most things a run for their money in the fast flowing or tight twisties. Suspension gives plenty of adjustment to suit the rider.
Have just recently replaced the clutch slave cylinder with an after market version as John mentioned above, mine started leaking and the clutch starts to drag. Not found it particularly thirsty bike but not really kept an eye on fuel. Probably get around 150 mls touring on a full tank from memory and the bike (I) will happily sit at 90-100 all day, some might be comfortable at a higher speed.
Would I recommend one - absolutely! great bikes....or even the newer 1050??
