Is more amp power always better...?

Type of quality power matters too.  It's not just about quantity of power for me.   

Rotating now between my tube amps to my solid state amps, for many years, formerly i used decent 200-300w dual mono Class AB amps. Nice full sound, yes. True Class A sound, NO.  I'm back to experimenting with this a lot again recently.   

Now trying the upgraded 50w Class A solid state amp again this winter. Its a bit more lean first 45m of warmup. Once its fully warm and toasty past 60m to 120m, the Class A 50w SS amp is more magical and engaging to listen to than my more powerful Class AB 200-300w amps were. Particularly at low volume levels too. 

Would I say the more powerful solid state amps sound better in this case?  No.  

There are days the Class A 50w solid state mosfet amplifier also puts my other two Tube Mono 100w amps to a challenge of sitting for a while longer. 

Lots of good advice here. If you can find an impedance graph for your speakers and see that they spend time at 4 ohms or below, you will want to ensure that the amp doubles or comes close to doubling wattage when impedance drops to that level. Another thing you may want to look at is how many watts of class A are available before A/B kicks in. But as many have already stated, specs alone do not tell the whole story, in the end it has to sound good to you. 

If you want to see  the impedance curve you can use Room EQ Wizard with a home built wiring jig to measure it, or you can buy Dayton Audio DATS (what I use) to chart it. 

@zlone Lots of good advice here. If you can find an impedance graph for your speakers and see that they spend time at 4 ohms or below, you will want to ensure that the amp doubles or comes close to doubling wattage when impedance drops to that level. Another thing you may want to look at is how many watts of class A are available before A/B kicks in. But as many have already stated, specs alone do not tell the whole story, in the end it has to sound good to you.

Channeling @atmasphere who might chime in on this topic, and explaining more about "how" and "why". My pure Class A solid state 50w amp with mosfet opts (always on, biased full Class A), sounds better than my other Class AB amps where the first 10w was supposed to be Class A. Not sure why exactly. I just know the pure Class A just sounds better in my setup once everything is good and warmed up - fwtw.

@decooney My pure Class A solid state 50w amp with mosfet opts (always on), sounds better than my other Class AB amps where the first 10w was supposed to be Class A.

Good point, pure Class A is another option. I am guessing that amps designed that way are simpler and on average probably deliver better sound. I considered it myself, but opted for a high current amp with 18 watts of Class A on the front end. Pretty sure I rarely cross that threshold these days.