Is more amp power always better...?

 All the specs. of an amp can help determine whether it is a good fit, but in my opinion the signal to noise and wattage will determine your headroom. For dynamic listening you must have headroom and that will take wattage.

How many ohm are the speakers ? 
150-200 wpc is a good average at 8 ohms and she be close to double the power into 4 ohms for any decent quality amp referring to SS .

the reserves are good for transient peaks to prevent distortion if playing loud.

with any room acoustic room panels are a big flus to reduce echo, reflections and distortions.

You want good quality.

This would give you class A power and enough of it. I'd say this would be your amp.

Just like a hot rod , more is better.

Being a bit underpowered at "normal" listening levels will result in some degree of dynamic compression. The result will not sound "wrong" or objectionable, just not as impactful, or with as much contrast between quiet sounds and loud ones. Severe clipping due to insufficient power at high listening levels is another story altogether. Not what we’re referring to here.

On the other hand, the "wrong" high powered amp will sound wrong to you, which would be objectionable.

So, pick an amp that sounds good to you.