Tube amp power watts equivalent to Solid State?

^ I would agree that the softer clipping of tubes might make the sound of tube amps seem louder than comparably powerful ss amps, but as tube Watts often cost more than ss Watts, one might be able to buy extra ss Watts for the same money to compensate for the clipping issue, and perhaps more readily dismiss it altogether. Perhaps it might be wiser to compare amps on the basis of cost rather than Watts? Of course, that is not to say one shouldn't consider power output ability when purchasing appropriate amplification.
Is this "...excess of electrons near the plate." consistent and/or linear?
Sorry but, I'm not sure that "This is why guitar players tend to prefer tube guitar amps BTW." is necessarily true. Creating sounds is quite a bit different than replicating them.

Interesting thread, and think this comment by Atmasphere is very significant,

Because some odd orders and in general higher ordered harmonics are present, which the ear uses as loudness cues, the amp will just tend to sound louder at this point, but without breakup that accompanies hard clipping.

as I have read many times that the distortion created by the soft, gradual clipping of a tube amp is perceived by the human ear as an increase in loudness, therefore thinking tube amp watts are more powerful.

As far as guitar amps, I have read that there can be a difference in the design of the volume control circuit between tube and solid state. A solid state amp will reach maximum output with it's VC at very close to fully clockwise to avoid hard clipping, while a tube amp will reach maximum with the VC at only 3/4 of the rotation. This allows adjustment for varying amounts of that desired distortion in a tube amp.

Best to avoid clipping totally, however # watts it takes.

As long as its done well.....

I answer to jmcgrogan2's question and to follow up on Drussheaxe's response:
Current US law dictates that:
mercantile products (cotton) are weighed in Avoirdupois ounces
physical bullion (gold) are weighed in Troy ounces.
Avoirdupois ounce = 28.349 grams
Troy ounce = 31.10 grams
Avoirdupois pound = 16 Avoirdupois ounces
Troy pound = 12 Troy ounces
Avoirdupois pound = 453.504 Avoirdupois grams
Troy pound = 373.2 grams
10 pounds of cotton = 4.53584 Kilograms
10 pounds of gold = 3.732 Kilograms

I've owned many tube amps during my 45 years as a musician, sound technician, stunningly handsome bon vivant, and amazingly interesting gasbag. There is not only an appealing tone with tube guitar amps, but a tactile quality that experienced guitar players understand and is sometimes described as "snappiness" or "finger response" or other things I can't remember (I'm old...so SUE ME)...I have also owned a highly regarded (for its time) SS amp, and used it for a while until realizing it sucked. I just bought a cute little Class D Ampeg bass amp that sounds fine, so exceptions are made..."Modeling Amps" also are somewhat popular here and there, but I don't like them. None of this may matter, but I like to take any opportunity to talk about myself hoping that people will like me.