I've got Ashly pro-amps in my setup. Sound is a somewhat subjective thing. I wouldn't necessarily say that all amplifiers sound the same, but there's definitely nothing wrong with using pro amps. I like my Ashlys because they have power to spare, and I feel like they give sound (especially bass) a bit more punch compared to powering the speakers from a receiver.
I also got them because I intend to build some DIY speakers at some point, which would likely be 4 ohm, and I needed amps that could drive that load.
As to why *not* to use a pro-amp - there are a few reasons I can think of offhand. The first is fan noise. Most pro-amps have cooling fans. If you value silence, then pro-amps may not be for you. In my case, there's a computer running in the living room 24/7 anyway, which makes just as much noise as the amps, so I don't really pay it much mind.
Some people disable/slow down/replace the fans in their pro-amps for home use. This is also an option - but does carry some measure of risk. So far mine haven't caused enough trouble to mess with.
Another thing to think about is signal levels. Pro gear is generally designed to work with a higher line level than consumer gear. I haven't actually found this to be a problem so far. My amps are hooked directly to the pre-outs on my receiver, and it sounds fine.
Lastly, most pro gear is designed to use XLR or 1/4" balanced connections, while home stuff generally uses RCA unbalanced connections. Again, get some RCA->XLR adapter cables and it ought to work fine. You could get something like an ART CleanBox that would do active conversion for you if you have problems. So far, I haven't seen a need.
Basically, when it comes down to it, the only potential showstopper is fan noise. You can decide if that bothers you or not.