Power, watts or amperage isn't going to tell how an amplifier will sound compared to another. I can only provide you my real life experience with Jeff Rowland products. I had a Jeff Rowland Continuum S2 Integrated Amp. The S2 is rated at 400 watts @ 8 ohms / 800 watts @ 4 ohms. I traded the S2 to purchase the 625 S2 amp. The 625 S2 is rated at 325 watts @ 8 ohms / 600 watts @ 4 ohms. Everything about the 625 S2 is better...the soundstage, bass, mids, highs, tonality. Unfortunately, specification don't always give an indication of how an amplifier is going to sound. The Continuum S2 is Class D and the 625 S2 is Class AB. My point is there are other factors that determine an amps sound that has absolutely nothing to do with its power rating. In my opinion, it's better to spend extra money to get a better sounding amplifier; not necessarily a more power amp!
WHAT'S THE DEAL WITH WATTS?
I'm considering acquiring a new (for me) integrated, under $2k, to drive my KEF full range speakers. They are very efficient (93db) , 4ohm and rated for 50 - 200 watts. It seems that a good amp with 80 or 100 watts per channel at 8 ohms will take these speakers to any volume I'd want to experience in my medium sized living room. So what advantage/benefit in sound am I going to get with 150 -200 watts, or more, per channel? Is it worth spending more for extra power that will never really be demanded?