Do Mono Block amps provide better sound ??

In a word, yes

it is like Spencer wrote. Depends on quality of course, but when you try same as mono you will hear the difference. Even with high sensitive Horn Speakers it is a better result (from my experience).

I have always found that a better quality stereo amp is better than 2 average mono amps. When you have superb amp, then mono amps provide just a bit more...this should be the last thing to do...after getting a top of the line Aye, AudioResearch, etc.

I've demoed several same brand stereo /mono amps and have heard no sonic advantage either way . The stereo amps were considerably cheaper so the choice was easy .

I have owned many different high end stereo amps and monoblocks. They have all sounded good to me, but you have to remember each amp has it's own sound. If the monoblocks sound better in your system, and you prefer the set up (length of speaker cables and interconnects, set up off your main rack) and price increase then go for it. I don't think you can go wrong with a good monoblock or stereo amp.

All things being equal, though they rarely ever are...mono blocks offer one important element--better channel separation.
Crosstalk from channel to channel and suspect power supplies are the bane of some Stereo designs, hence 'we're dual mono designs' from people like Gryphon.
If nothing else the separation can give a more satisfying stereo rendition...a notable goal.

Larry