Sorry, me again. Just read your OP properly... I only looked at this one nursery as we were on a two day visit to the area and never managed to get any more appts. They do only do appts to show people round, no impromptu visits (or so they say). Luckily I liked it immediately, and it is within 5 mins walk from our house so it seemed perfect.
I mainly based it on gut feeling to be honest. I warmed to all the staff I met immediately, the children there looked happy (looked at one in London before we moved and the kids looked miserable, moping around and didn't look entertained).
Other things that I am happy about are they feed them a proper hot meal for lunch, there is a large outside area for play as well as inside, they learn through play, they have good security, it is clean and all the toys look in good condition. Mainly they seem genuinely happy to see DS when I drop him off (he does cry whenever I leave but as others have said it is momentary and he has stopped before i have even left).
Sorry, rambling on.
Finally, about settling in. Obviously your DD may have more settling in than my DS as she would be going for longer, but we had two settling in sessions. First one I took him at 10:30, stayed about 15 mins chatting to staff while he played, then left him for 30 mins and collected him. Second time I took him at 9:30, left after a few mins and collected him at 11. He then started the following week and I left him at 8:30ish and collected him at 12:30ish.
This one is open 51 weeks a year (closed one week at Christmas), and also very flexible if you want to leave your child for an extra half day / day etc (ie when I go for hospital appts and it is easier to go child-free). The only time he has looked a bit red faced and puffy eyed when I collected him is when I left him from 9am to 5:30pm once and he was apparently a bit upset for the last half hour, probably wondering if I was ever coming back .