Tube Watts vs. Solid State Watts - Any credence?


I've heard numerous times that Tube watts are not the same as Solid State watts when it comes to amps running speakers. For example, a 70 watt tube amp provides more power than a 140 watt solid state amp. Is there any credence to this or just sales talk and misguided listeners? If so, how could this be? One reason I ask is a lot of speakers recommend 50 - 300 watts of amplification but many stores have 35 watt tube amps or 50 watts tube amps running them. More power is usually better to run speakers, so why am I always hearing this stuff about a tube watt is greater than a solid state watt?
djfst
Gee, in all this time on this thread no one has bothered to mention the most distinguishing feature of tube amps vs solid state amps. That is the lack of the irritating harmonics present in solid state amps.

Actually I did allude to that earlier...
"That is the lack of the irritating harmonics present in solid state amps."

Present in many perhaps but not all.
All Class D amps I have heard are the opposite of irritating. Go listen and see which ones you find irritating or not. I've heard Bel Canto and Rowland mostly.

Atmasphere has cited certain Pass amps and others I recall that are not prone to irritating harmonics as well. He would know best probably.