Is there any truth to this question?

"I have 4 ohm speakers being driven by a 150wpc into 4 ohm amp. Say I never go louder than 3 watts. I should have enough power for all peaks and dynamic events.
Say I then replace that 150wpc @ 4 ohm amp with one rated at 300wpc into 4 ohms. I still listen at 3 watts. Will I have gained anything? "

I'd say the answer is: it depends.

Digital in particular is very challenging for an amp to deliver peaks and transients. I am of the opinion that this has always been a major reason why digital does not sound good to many, ie their amp cannot deliver the peaks and transients accurately to the speakers. A good, well constructed amp selected specifically for its ability to drive the speakers efortlessly can. I have found that going with more power in general helps, especially as the volume goes up. THe amp has to be good. IF its a good amp, the extra power becomes an insurance policy at minimum. In general, I believe this is where one wants to be.

Since most music is played in the home with I'm guessing 1-3 watts on average, and all that additonal power is needed for handling short term transients, it might certainly explain why you need much lower power from a tube amp compared with an SS amp to play equally loud (why watts aren't watts) - you need a lot more reserve power in an SS amp to avoid the harsheness of SS clipping, while clipping is relatively smooth and unobtrusive with a tube amp - a major difference between the two.

It might explain why Roger Modjeski built himself a 35 watt tube amp, when he could build anything, to drive his 87db Vandersteens and thinking it was sufficient power. I suspect with SS you really do need that extra margin of reserve power to avoid the clipping nasties - fortunately SS watts come alot cheaper than tube watts.

Agree with pubul that addressing clipping with a tube amp is different than for SS amps in general. Tube amps tend towards soft clipping which is more gradual and generally less offensive allowing for fewer watts.

Not all clipping occurs similarly however. Clipping always results in distortions, regardless of how offensive or not those may be, and is never a good thing.

Pubul, that brings up a great point. SS isn't necessarily cheaper. New the YBA stuff was over $5K not that I spent that. The RM 10 is $1995, a Rogue Cronus Magnum integrated with 90 watts is $2200. In that regard tubes sound better and better as an option to high powered SS. I'll live with the YBA and save my money and next time I probably buy tubes.

If the sound levels increase and the sound continues to expand in proportion as you turn up the volume, that is a good indicator that clipping is under control.

If the sound stops getting louder in proportion to how much you increase the volume, even if you do not hear obvious distortion, clipping is probably in play.

This applies to any amp, tube or SS, although the audible distortion effects with the tube amp is likely to be significantly less and may seem non-offensive.

You would likely hear a difference in the dynamics and clarity of transients between any two amps, SS or tube, if one is clipping and the other is not, all other things aside, at least with some better and more challenging recordings.