That's a pretty vague question. I don't think anyone will be able to answer it honestly(perhaps a select few). Which do you like better chicken or steak?
i heard the Boulder at a dealer a few times and wasn't impressed (it seemed grainy and dark).....but i would add that i never cared for the overall system it was in...Wisdom speakers that were never properly dialed in....they couldn't figure out the Wisdom "brain" properly.....so discount my comments accordingly. i have been told by people i respect that Boulder amps are very special. and i would point out that i have been told that the Boulder is grain-free and very open in contrast with my own observations.
my 2 favorite solid-state amps are the Halcro and the Edge.
i had the Halcro DM-58 in my system for 3 days last year and it is very special....the fastest, most transparent, most detailed amp i have heard.....but.....it may be too lean sounding for some systems/speakers. i heard both the Halcro and the Edge amps at CES and there i preferred the Edge ($30k monoblocks)....it was mated to the Lumin White (sp?) speakers. easily the most "musical" and "edge-less" solid state amps i have heard.
i would guess these 3 solid state amps are all winners in the "right" system (if you want a ss amp ;^)
i would choose the Edge, then Halcro, and then the Boulder based on my experiences and listening preferences.
I haven't heard the 1000-watt, sixtysomething grand Boulders, but I do prefer the mid-priced thirtysomething grand Boulders to the Halcros.
I recently heard an amplifier that, to my ears, significantly outclasses all other large solid state amps. That is the 400-pound, thirty-grand GamuT stereo amp. I would imagine the monoblocks would be even better.
When I heard the big GamuT amp at CES 2002, it was driving a pair of Wisdom Audio speakers, which I'd previously heard being driven by several large amplifiers, including a comparably-priced pair of very well respected monoblocks. I had been so far unimpressed with the Wisdoms. But with the big GamuT amp, the Wisdoms were full of life and impact with absolutely no harshness. In fact, the volume level was so loud I had to shout to my girlfriend to communicate with her, but the music sounded utterly natural and didn't hurt our ears! In my experience only unamplified live music sounds so good at such high volumes.
The thing that really struck me about the big GamuT was the coherence - it was like what you get from a single-ended triode amp. I think it's because the GamuT uses just a SINGLE ultra high quality MOSFET per side, so instead of hearing a chorus of closely-matched transistors you're hearing a single voice. And I'm sure the behemoth power supply didn't hurt.
I heard the amps MikeLavigne mentioned, and the Boulders weren't driving speakers in the same league as the Lumenwhites that the Edge amps had. Those are both superb amps, and so is the Boulder, but the big GamuT just does things I've never heard an amplifier do before. And since I've heard the Wisdoms on several occasions and never liked them before, the GamuT gets extra credit in my book for bringing them to life.
Well I'm starting to sound too much like a salesman here, and frankly I don't even have the big GamuT on display yet. But if I had to choose my last solid state amplifier today, that would be it.