It's a bit of a tough choice. There are some things to consider:
How far away is each school?
Are you C of E? (not very important but could be a factor)
How old does each school go to? (Year 3, 6 or 8?)
Does either school have a waiting list?
What are the results like at the end of schooling?
Are you working and do you need after school care?
How many other children do you have, how does that tie in with after school care, would your younger DCs get places at the the same school as DC1?
I would be tempted to go for the smaller school because:
-class size is very important to me
-the teachers are great (in your words)
-sounds more socially supportive
However: if the village school goes to Year 8 I would not choose it because 20 children in a yeargroup(?) or class gets a bit stale around 10/11/12 but is generally nice if you are leaving in year 6.
Also I am not a big fan of open plan classrooms.
The benefits of the larger schools are obvious but bear in mind that usually after school clubs etc are not that great until the children are Year 4 or so.
I can't really comment on social/cultural/ethnic diversity, this point has never been very important to me (is that bad?). I have found that if, in general, there are a few children of each minority everybody is forced to mix but if there are two large groups then sometimes there can be a self-imposed divide but this is usually at secondary level not primary and is certainly not universal.
Look into the pastoral care side of things, ask how each school stretches particularly bright children and how they support underachieving children.
So for your question on experiences in these types of schools:
For primary, I went to a small all girls school, between 3 and 21 girls to a class from R to Year 6, when I proceeded to the attached senior school. It was a lovely, small school with great teaching and a good music curriculum, P.E. department and library. I loved the school. It did have good ethnic mix for the area (very white neighbourhood, the school attracted a lot of asian families and, when I was in year 1, the only black girl within 20 miles... we were all very jealous that she didn't have to wear sunscreen!)
I don't have any family members in primary school at the moment, but my neighbours have are sending their four younger children (two sets of neighbours) to the local primary which is co-ed and has 900 children, classes up to 32. They all seem happy enough and the children are doing quite well though the school has a very mixed reputation around Years 5-8 as to academic achievement.
This has turned into a very long answer! Really, just ask around, ask parents at the schools, and then pick one (or can you apply to both?) it seems both choices are perfectly good and it won't matter either way.