True what they're saying about the big "corporate" schools but be wary of the small outfits that only have one or two planes and one or two instructors. I started out that way and found that a bunch of my lessons were being cancelled because the plane was down for maintainance, or my instructor had to go do a charter flight. So I switched to a place with a sizeable fleet and a more significant number of instructors.

Also, part 141 schools have an advantage here because their syllabi are so regimented that even if your instructor has to bail on you some days, another one can step in and pick right up where the former left off, so the student has a more-or-less seamless transition. And in the long run, if you're going all the way through commercial, you may see a reduction in the number of hours it takes to get there.