I run a 2001 GS500E .. for info on GS500's and stuff go to
www.gstwin.com (main site) and
www.gstwins.com/forum/ for the forums.
Yeah suzuki discontinued it for 2003 but you can get it elsewhere int eh world. They stopped it because in the US the GS500 wasnt selling as much as the GSXR's.. newbie's were going for more powerful bikes and hence they make more of a profit when those idiots crash and come back to buy another new one..
But the GS500 is teh best all round bike that is nolonger available in teh US as new (cycle world June 2003).
Check out the GStwin forums and you should find all your answers there.
As for problems and senstivitity.. the GS500 has a rust problem and the suspension is quite soft (I have replaced my rear shock with a katana 600 shock the front will be replaced soon too). The carbs are tuned funny, its tuned to be lean, using srinath's formula (89-00 bikes) can be made to work like normal. In 2001 - 2002 the carbs are differnet and we are yet to find a reliable carb jet solution other than Factory Pro and or DynoJet (both very expensive).
If you like tinkering with bikes, modding stuff etc etc.. this is the perfect bike. We have to salvage parts of other bikes to get ours to be absolutely custom. Pablo (on the gstwin board) has a bandit 400 rear hugger, a ducati front fairing, etc etc..
Anwyway the gs500 is the best bike.. it handles like a dream, its fast but not too fast that you will get killed and over all its a really sweet bike. I love mine.
TGG