Well mine is just under 4,000 miles old, and it is quite frankly the best bike i have ridden in my life (my 5 year biking career has included 600s, a few VFRs, an 03 blade (for a day) a Pan (for a day) a Trumpet (for a day), CB500 and a few other oddiments)
Whenever my VFR was in for a service i used to have a CB500, it was a highly entertaining bike, the upright seating, the brilliant handling, pegs down everywhere, and when the engine was on full boil it was respectably quick, its a brilliant commuter hack...almost my ideal bike
then i rode the 12GS, its just a bigger version of my ideal bike, it has shedloads of torque and just as the torque begins to fade the power kicks in, giving almost seamless power delivery and grunt, fantastic handling, will keep up with 600s on the straights at full pelt, brakes better than a 999, yet has the most fantatstic levels of comfort, it is truly fantastic; If you want to cruise settle back and let the torque carry you along, if you want to give it some welly it will truly entertain and is good for 130mph. It is very confidence inspiring in wet or dry and you will find yourself riding quicker and more smoothly, the view is superb, you can really pick out the hazards, and sometimes you'll find yourself just enjoying the view.
I have a very boring 25 mile (each way) commute into the smog every day, i smile when i get on the GS in the morning, and i can't wait to get back on it to go home again...rain or shine it makes no difference.
Problems....none, it is superb...my 2 previous VFRs (VTECs) suffered fuelling issues, the second one had all sorts of things go wrong...my GS...just incredible, great dealer, fantastic bike, ideal for potholed, camera lined roads...don't get me wrong blades and R1s are great (for the track) but GS is just better, cruise, commute, blat...best bloody bike on the planet IMHO