So - one mediocre and one good.
DS went into a largeish nursery (large group owned) at 4 months. Building was brand new, built for purpose, and 200yds from home. The baby room was fantastic, they had a chef onsite who really cared about what the DC ate, they were completely chilled about us bringing in DS whenever suited us (so we would give him a late start if we could, although we were paying for whole days), we went through weaning as a collaborative process, we got loads of info every day. As DS went up through the rooms, all was still fine, they moved him with friends rather than worrying about artificial age boundaries, etc.
The issue was that they were losing money. The group was taken over, and the new management started cutting one thing after another. Things that had been included became extras, the chef had central purchasing forced on her so she wasn't in control of the quality of her ingredients, she wasn't "allowed" to get involved with cooking with the DC (which they loved) and she eventually left. Staff turnover shot up. They started trying to impose age barriers, and then when DS colluded with one of the remaining nice staff to get himself moved into the preschool group 6 months earlier because all his friends had been moved, the horrid room manager (a) tried to label DS "a biter" because he once bit back having been bitten and (b) made a huge issue that he "wouldn't separate well from parents" because he hated being left with her - was fine with everyone else.
I had numerous meetings with manager and was fobbed off. If we hadn't been moving I would have moved him, but nasty room manager aside he was happy and it wasn't worth 2 moves in quick succession.
DD, OTOH, went, at 6 months, to a small, community run, not-for-profit nursery. They were fab. Incredibly low staff turnover, lots of mums and grannies of nursery DC working there, family atmosphere. Scruffy (but well-maintained) portacabin-based building, but lots of care and attention into outside areas as well as inside, energy and imagination put into everything, etc, etc.
She did messy play, rhythm time, tumble tots - all the things I could never face, she did with nursery workers who entered into it with enthusiasm. They knew her and understood her. It didn't stop there being phases when she would wail when left, but there was always someone to hand her over to and I would hover out of sight and listen as she stopped crying within 30 seconds. On the vast majority of days she was happy to go, and happy to come home.
She still looks forward to seeing all the staff when she goes to the holiday clubs that they run, and some of them babysit for us occasionally. I would (and do) recommend this particular nursery to anyone.
That was an epic - sorry!