A post at Mommy/Prof's blog reminded me about how hard it was for us as parents of a toddler and first grader back when we moved here about four years ago. When you move, you typically lose your support system of neighbors/friends that can help out in a pinch.
Plus, in a new job it is hard to insist, "All meetings must end at 5pm sharp so I can pick up my kids before daycare calls child services! No, seriously, stop talking! I'm leaving! You better not make any important decisions once I'm gone....!"
We were so pressed for time when we first arrived that I put my toddler in one of those commercial daycare centers--a chain. By the time I got there (5:15), it seemed every kid was bawling and the daycare workers seemed totally frazzled.
So I did my homework and we found a woman near the elementary school that did daycare of young kids and then had elementary kids come over once school got out. This was far better for the kids, and both were quite happy there.
Unfortunately, the woman slowly drove us absolutely nuts. We had to pick up by 5pm (who gets off work at 4:30?). But sometimes she'd take the kids on an afternoon outing, in which case she'd never get them back by 5pm and we'd all just sit in her living room waiting. She did not provide lunch or snacks, but had complicated rules about what types of lunches on what days. Despite her own rules and her training as a nurse, she fed my daughter raw cake batter, at which point we discovered that my daughter is allergic to eggs.
And in addition to those and many other issues, there was something about her personality that was completely noxious to adults. But all the parents kept up the appearance of getting along with her. After a year and a half, we finally couldn't take it anymore and left. That set off the rest of the parents, who also quit. Now, 2.5 years later we parents still run into each other and vent about how stressful and perfectly awful she was (only for parents; kids still remember the time with great fondness and they also learned a lot from her).
My lesson from all that was that daycare needs to work for both parents and kids. The research I've come across on preschool is that once it is above a certain basic level in terms of quality, kids turn out fine and without great variances in outcomes.