I find that a random unnanounced visit to look at a daycare centre shows them in all their glory. But be sure not to go during the middle of the day, because chances are staff are on lunch breaks and children will be resting.
I once had my DD in a centre that seemed great on the surface, but due to other commitments began picking her up at totally random times during the day. It didn't matter what time I turned up the kids would be watching a DVD! WTF? For the cost of the daycare I could've been buying a new DVD everyday and sat her in front of the TV at home!

Good Luck!