Clayton M100 Monoblocks??

Are these amps as good as the reviews say? Comparable to? Pass X series amps?
Well, let me start out with the disclaimer - I'm a Clayton dealer. But I was a Clayton owner before I became a dealer. The M100 presents an excellent combination of liveliness and harmonic richness. However, before I could recommend this (or any other) amp, I'd want to know what speakers you were planning to drive with 'em.

You mention Pass amps - another excellent line (which I do not sell). I'd say that the Claytons do some things better than the Pass X series amps, and the Pass amps do some things better. Once again, it depends on what qualities you want to maximize.
I am currently running platinum solos (small bookshelfs very inefficient 84db and 6 ohms) I plan on staying with bookshelfs inthe future so I guess whatever speaker I get will need power!

I infer from your email that most/many book-shelf speakers are inefficient. Is that what you meant to say?

If so, I dis-agree! Atleast 1 model from GR Research (Diluceo) & the one from Green Mountain, several from B&W & from Dynaudio are of much higher efficiency: 89 - 91dB.

There was a very good review I read on the M100 recently that said that it "loves" a low imp. speaker: 4-8 Ohms but the reviewer wouldn't use it w/ a speaker w/ over 8 ohms imp. Here is the link to the review, if you haven't read it already:

I eyed these amps very longingly but ended up getting something else (which I'm very happy with, BTW). FWIW.
I am a little late in responding but I will say this amp is superb. A natural balance from top to bottom but dynamic if the material demands it. Two distinct areas of excellance is top end and midrange are consistently well balanced tonally.

Bass is very good although my speaker low frequency is limited.

A+ rating in my book.
You may consider the S-40, which should be more than enough to power any bookshelf.

I used to own the M100, to this date, I ranked it high on my top amp list. As I upgraded to ATC active 50's, I could no longer use the Clayton. Prior to Clayton, I have used ML, ARC, and other Stereophile Class A amp.

When I moved from the 200W ML to M100, I got extra bass energy, and the midrange smoothed out (almost like tube), but it has all the dynamics of the solid state.

One thing about Clayton: to my ear, most tube has more residual noise, but the residual noise seems to be a layer infront or behind the soundstage. With typical solid state, the residual noise seems to be surrounding each instruments within the sound stage. I really think this is the main difference to me. With better solid state such as M100, I almost could not hear the noise surrounding the instrument, and none of the 'noise veil' similar to tube amp as well.

The M100 is better than ATC active 50's built in amps, but elimination of crossover and speaker cables are major benefits going actives. It is a trade-off thing.
Here's an interesting review from a few years back: