what are the pros and cons of either amp power specification?

rlj

What are the pros and cons of either amp: 1) an amp that is 100watts at 4 ohms and 50 watts into 8 ohms or 2) an amp that is rated at 75 watts into either 4 ohms and 8 ohms speakers?

In a word: Nothing. Taken by itself, the spec doesn't tell you how the amp will sound.

Good answers

Best performance not Always = best sound. Best sound is totally subjective. But you have a better chance at best sound when performance is good.

So if you have the typical modest load speaker that would probably make me lean towards the amp that increases power into a lower impedance for best performance ie lower distortion At least based on specs which tend to give at least a clue about what to expect even if juiced somewhat.

The one that doesn’t could still sound better and may even perform well if the speakers are designed to be an easier load.

So its always an educated guess until you actually try and find out. Some educated guesses are better than others. But you have to decide somehow which to try that has best chance to sound good.

Best would be to try different options and see. Unless you get it right the first time. It happens.  Chances are best with a highly educated guess. 

It depends on the load of the speakers the amp will drive.

This subject was covered exhaustively in a 1981 documentary that gave it all the seriousness and respect it deserves:  https://youtu.be/6iCbK3ooekU?t=24

I missed typed the Sprout100 specs its 100Watts into 4 ohms and 50 watts into 8 ohms which I'm comparing to the Bluesound POWERNODE2021 power output.