thegrowlygus, are you looking at Bunnybrooke's or the new KU out on Long Road? My eldest boy went to Bunnybrookes all the way through his nursery years and coped fine, but I know a lot of children haven't.
My daughter (20 months) is currently at Long Road KU. The staff are a mixed bag, to be honest - some of them are lovely, experienced, cheerful (one or two that have been there or at Bunnybrooke's since my eldest - now 8! - was there); some of them are grumpy, unmotivated teenagers that ignore you when you come to pick your child up and haven't got a clue what she's been up to if it hasn't been written down on the sheet. They have had a LOT of staff turnover recently, particularly at the management level, so it feels quite unsettled.
Why, you will no doubt ask, do I then keep my daughter there? Well - she is now settled in to her current room; both settling in when she first went, and then re-settling when she moved rooms in September, have been very bumpy journeys, so I know moving her around too often is not a good idea. Her particular 'named carers' are lovely. There is some flexibility about which sessions you take, in half-day slots. My husband also works at Addenbrooke's so it's logistically and financially easier, for the most part. Plus the nursery was purpose-built only about 3 years ago, so the facilities really are fantastic.
My middle son went to Joint Colleges for his pre-school years (nearly 3 - school age), and I would highly recommend it, particularly for children who are a little bit shy, as it's quite a bit quieter than the average nursery. The staff have mostly been there for years and years, it's got a lovely homey feel to it (the staff wear their own clothes rather than uniform, they're not afraid to give the kids hugs if they need them, they cope really well with fussy eaters, etc. etc.), the pre-school education is really excellent, and the other children are very motivated, as its intake is significantly from children from university academics and staff from the university press. One really nice thing is that they mix the age-groups up regularly for general play sessions, so the children socialise very well across age ranges.
The real drawbacks are the price - although as akent says above, not particularly bad by Cambridge standards (it just looks pricey when you stack it up against discounted rates at Addies; cheaper than Harvey Road); and the flexibility: like Harvey Road, you can only book five days a week (mornings, afternoons, or full days), so if you want to work, say, 2.5 days a week, you find yourself stuck paying for a full-time place.
My friends who have sent children to the Sunflower have loved it, but it's usually quite full, and it's not desperately convenient for the south of the city. Similarly heard good things about ACE and Snap in Chesterton.
One thing to consider with Addies is that as well as the staff discount rate, you can pay all your nursery fees out of salary sacrifice (not just the £273 or whatever it is voucher), which does make a sizeable difference once you get past a certain number of sessions.
The primary schools round south city are all pretty good BUT: watch out for Ridgefield (attached to Coleridge Community College), which takes a lot of kids from the estates with behavioural problems; also the Fawcett in Trumpington has similar issues.
The catchment areas are very, very odd (e.g. when we were living in student accommodation near the Botanical Gardens, our catchment school was the Fawcett - 2 miles out of town), so it is definitely worth getting a copy of the primary school application book, which has a massive list of catchment schools by street in the back, and keeping an eye on that when you're looking for a house. The popular ones are always oversubscribed.
Hope that's useful, and good luck with the move!
Cheers,
Rachael