Any advice? Parasound A21, Ayre V5xe, Benchmark AHB2, or Bryston 4B3?

Check out Hegel. They're coming up somewhat regularly on ebay and here for ~25 to 40% off list

we just purchased a hilo by parasound and love the unit.  you should audition what you like at the $2500 to $3500 price point but would not go wrong with Parasound in my opinion.

I have an all Ayre sysrem... all of their components sound best when you use them in balanced mode. ..never had any issues with any of their stuff.  Recommended

I have owned an A21 since January and only heard it through my Martin Logan speakers, so cannot compare to other amps/speakers as others here can.  I can say that my amp does not run hot . . slightly warm only . . but I have it open to room air and would recommend that.  

For that price range, Parasound has an updated model with more power, the A21+, which might be a better comparison to the other models you are looking at.  Normally $3,000, I’ve seen the A21+ on sale recently for about $2,500.

AHB2 has the most resolving power of the amps mentioned.. can’t believe someone stated otherwise.