We are HEing because, through church, I got to know several HE families when DS was very young, and I thought it looked fantastic.
I especially agree with CarmenSanDiego about the freedom thing- I think not having to fit into anyone else's schedule has made having DD2 a lot less hard work.
Also, like Marjoriew I'm so excited about learning everything again along with the DC's. No textbooks or (probably) workbooks, just brilliant book after brilliant book. We're reading Alice in Wonderland, which I haven't read before.
I've seen the worry my friends go through about nursery and school places, and all the things that are happening to their children in school, and I think 'we're well out of that!'
As for what DS might be like, my in-laws would tell you his tantrums would be cured if he were in school. I think they'll be cured when he stops being 4! I sometimes feel bad that we don't do as many 'activities' as nursery/reception, but actually I want my DCs with their family rather than cutting and sticking. DS does go to football and Sunday School and there he's no different from 'schooled' children, he can sit nicely, follow instructions, join in etc. I get lots of comments about how well behaved he is! Above tantrums let it not go to my head though!