Does the power of an amplifier really matter?

Number1, yours is a dilemma common to many of us.

There are no easy answers in spite of what the measurists would have you believe. The ability to maintain voltage in the face of low impedances...IOW the ability to deliver high current...probably is one factor, and the amp's sound at and beyond clipping probably is another.

Amplifier power is just a beginning, and probably not a very good one.
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I just wish I could get a handle on that nebulous amp attribute that allows a 100W amp to shine over a 200W amp

Or, vice-versa of course. Very robust power supply /rectification, matched output devices, carefully chosen components, application of feedback, etc, etc. So many things that are NOT visible to the naked eye...

BTW, regarding spl's, in the near field, ribbons lose about 3db per doubling of distance vs 6db for cones. A difference of 20db spl b/ween sound 1 and sound 2 means 2 is ten times louder than one. To achieve an extra 20 db difference you need an extra 100W of electrical energy. Accordingly, 250W should achieve ~24db. If you want 40db headroom (ie 100 times louder) you need 10.000W. Classical music often has 30db differences. Under normal conditions, that would require 1000W over the reference low passage.
Depressing isn't it:)
Fortunately, we usually listen at low spls and consume milliwatts of our amp's power, so there is headroom enough even with a 50-100W amp -- or less -- for the forte.

So when the cannon goes off in the 1812 Overture, you guys don't use the subwoofer to take over? Does any body know what's the frequency of that canon in the Overture? Your full size speakers can deliver such power and such low frequency? I am just in awe, and I am afraid to find out what speakers do you guys have b/c I may inherit a bug that I cannot afford. However, please do tell, and I am all ears. :> )

Some "low powered "amps will power speakers that simply don't work with other amp designs with much more power. The vintage Levinson ML9 (get that right?) was a pure class A monaural design with a whopping 25 watts into 8 ohms....and 50 into 4.....and 100 into 2....and 200 into 1...and it WAS rated at 400 into 0.5 ohms....

I would pick up a pair of these if they show up in good condition at the right price in a heartbeat.

The levinson ML-9 is Class A/B and it was 100 watts per channel in 8 ohms. It is the same amp as the ML-3 which had 200 watts per channel. You are confused with the Levinson ML-2 which were mono 25 watts class A and were used with Quad speakers mostly at the time.