Altered Tails has done three spays (one adult cat, two kittens) and two neuters (both kittens) for me, and all of the cats were very well cared for. The staff are professional and no-nonsense. The waiting room and parking lot are clean, although occasionally noisy. I've seen plenty of small dogs (and medium, and big) here, and they had no problem with anesthetizing small female kittens, so I don't know what the previous reviewer is talking about.
I'm adopting a stray tom who needs vax and snippening. I'm bringing him to AT. 'nuff said?