I can give some feedback on both Baby Acorns and Toybox in Roath - as dd1 went to Acorns and dd2 goes to Toybox.
Baby Acorns - LOVELY. Our first choice for both girls - but they can get booked months, and months ahead - for obvious reasons. Dd1 went from 10.5mths to over 2yrs, before moving on to 'Big' Acorns on the next street. Staff are brilliant - friendly and professional. They're pretty good at working together with the parents, and I've always found them co-operative and helpful. I always felt as though they genuinely all liked working there, knew the individual children well, and dd1 was well looked after. The nursery looks bright, clean and cheerful inside and out, with a homely atmosphere for babies, and a lovely garden. There was always fun structured activities, different themes, and dd1 was forever bringing things home she'd baked, painted, or made in nursery, every week. She loved going and loved the staff. It's always a good sign when they run in without so much as a backward glance!
When your child leaves, they also present you with a file of work, photos and a written record of things they did throughout their time there. They really have some nice touches, like the children always get a present from Santa at Christmas, it's sweet. 'Big' Acorns is more of the same - except a little more school-ish, which personally I think is a good thing. Like having a qualified teacher on the premises to work with the children some days a week, doing homelinks, having library books, etc. They are also starting a Forest School on-site, so the children experience toasing marshmallows around a camp fire, going on bug hunts, sitting and reading in a tipi, etc. Such fun. Dd1 was sad to leave, but I think it was a great introduction and preparation to school, as well as providing her with some incredibly happy and treasured memories.
Toybox - GOOD. It was originally our second choice for dd2, but Baby Acorns was booked 8mths in advance when I made the enquiry, so went to Toybox instead, which is nearby. It has a similar homely feel, also cheerful and clean, well decorated, with a lovely garden. Dd2 has been going since about 11mths to now, and enjoys going. I'm not sure she loves it quite as much as dd1 loved Acorns, but she certainly enjoys it enough, for us to leave her where she is, rather than disrupt things. She is also a very confident child, and has a wide vocabulary for her age (more so than her sister did at a similar age), so she hasn't exactly lost out. The staff are friendly, warm, and perhaps a teensy bit less formal. The activities seem to be more based around free-play - and not quite as structured I think. On an ordinary week, dd2 brings less things she's made home, but Toybox also arranges more 'adventurous' trips out e.g. Children and family trip to Bristol's Noah's Ark Zoo, and tonight, having a Sausages and Sparklers evening, in lieu of bonfire night etc.
In a way I think it depends on the child, which one is preferable, but they're both good, with caring staff.