I don't know about Rutherford House or Ravenstone, but both our children both went to Belleville (the Meteor Street site) and we couldn't fault the experience. Whilst the Webb's Road site is much larger (three classes per year), Meteor has just one class per year and so as a result feels much more like a small community. Both the girls have flourished both academically and pastorally, and we have been absolutely delighted with the school.
As the poster above has said, they seem to get an education in 'real life' as well - they have both had a myriad of different class-mates, some with special needs and some with behavioral issues, but the kids always seem to rally around and protect these children, and give them total support - not something I would have expected. My eldest now goes to a private school so we had a bit of tutoring in her last year which helped focus her on what those schools were looking for (not something that Belleville would do, but I don't have an issue with that).
We have friends who sent their kids to Thomas's and honestly there is quite literally no difference between how they have all ended up. We're happy to spend the money on private secondary (although the reports from Bolingbroke Academy are excellent so I might have not even bothered with private if we were in that place again), but to be honest from our experience I would say that spending money on a private primary has not held the girls back in any way, shape or form. Our eldest is still really good friends with her class mates from Belleville, which is wonderful.
Good luck with your choices - as I have figured out over the years, whatever you choose will be the right choice for you and your children.