I have some experience with other B&W and ProAc. Maybe that can help a bit.
I have old B&W 802. It never sounds it's best with my amps (100W SS and tube). I know them can sound fantastic but I just don't have the right gear. They souned flat and less vivid/involving in my system comparing to ProAc. Some may say it's neutral though. Surprisingly, it didn't have much bass (in my system, anyway)
ProAc monitors don't really have bass. Super tablette virtually has no bass, and it's not the strength. They have very good tonal accuracy and almost pin-point positioning. I would recommend Response 2 if you insist in monitors. I have them for 7+ years in my system and am very happy with them. If you can go for floor standing, Response 1.5 is a much better choice and they fall in your budget range (used) ProAc monitors need (and deserve) good speakerstands which will set you back about $500.
I am using primarily tube amps (100w PP and/or 8w SET) to drive my ProAc Response 2.5 and Response 2. Listening to mostly classical music.
Matching with your existing gears (amp, pre-amp, wires, front-end, etc) is very important. Good speakers could sound terrible and disappointing.