Here's a couple of mid/hi end amps I have owned or auditioned extensively. They are all well reviewed and good value for the money -- especially used. Above this price point I believe you get dimishing performnace and thus have to spend a lot more to get noticeably better sound. Used, these amps can sometimes be find in the $2700 - $3500 rannge. The two SS amps are made in Canada, so you're also taking advantage of the lower CDN dollar Xchange against the US dollar.
Classe 301: lush and tube like, a touch laid back, but never lacking in power reserve. Doesn't care about hard to drive speakers. Seems to sit somewhere between Krell and tubes with respect to detail and "firmness". Classe Cam 350's are also very good, but I've not seen them used and they may be out of the price range you are considering.
SIM W5 - tons of power (make sure its the new 190W you consider, not the older 175W model). Firm botom end, tight and fast, not quite as sweet as the Classe, but excellent on most speakers. Stereophile gives it a class A rating, unusal for an SS amp costing under $5K new. After hearing it in a good room with some JM lab speakers, I agree with Stereophile -- this is both high performance AND value.
Also consider Aragon 8008. Not quite in league of the others, but can be had for about $1750 - $1900 used.
Above all, go listen BEFORE you make up your mind -- there are many good SS amps out there. If you wnat tubes, I recommend the Aranov 9100s - under $3K used - not well known, but decent bottom end for a tube. Likes a subwoofer to help out if you have inefficient speakers.
My current combo is Aranov 9100s and a Rel Stadium II helping out the bottom end. Liked it better than the Classe 301 and W5 (without the sub). My mains are flat to about 35Hz but I find the sub still gets rid of room problems, takes some of the workload off the tubes and gives me 80% of the SS bottom end. --Lorne