Just remember, there is always a trade off.
You can dive with a guarantee of fewer divers . . . but you won't have the same service, no matter who you sign up with.
One of the many reasons that people recommend Amigos is because they have so many boats, you are virtually guaranteed to get a dive, whereas with smaller operators, sometimes they don't go out if conditions and/or customers aren't all that they can be (to the operator)
Amigos will keep your gear, instead of having to take it with you all the time, etc. etc.
I almost always dive with Amigos. There is a reason that I do that, even with all my San Pedro diving experience . . .
I really enjoy diving with *very* small groups, (in fact, often dive sans buddy) and from time to time, I've had to put up with as many as 5 or 6 other divers (oh no). . . but it's rare and when I do, we are still quite comfortable and roomy on the Amigos boats (even the smallest one).
However, while you can find yourself from time to time sitting and diving with more divers than you'd hoped to, Amigos often don't have that many divers booked. And whether they do or don't, all of their boats are in really good shape, and as a rule their captains and DMS are excellent. I could go on and on and probably will . . .
All that said, if you are totally hooked on making sure you dive with a small intimate group with an excellent DM, then be sure to check out Ched (Reef Adventures).