I am one of five. I did enjoy it growing up, but we never had any money and there was about 3-4 years at least between us all so I don't think we were close as children. When I was aged 4-8 I played with my older brother but tbh I didn't enjoy it as he was a bit of a bully and my mum was too busy sorting other kids out to intervene. By the time I was 8 he was becoming a teenager and after that we barely spoke. Ditto for my two older siblings who were already in that stage by the time I was 4.
I preferred to play on my own really. We weren't really allowed friends around because my parents were too proud to let other people know we had no money and there was no spare food to give them tea etc.
Getting a job when I was 16 then leaving home to go to uni was really the making of me and when I feel my life began. I had money and independence. The first night in halls was weird - it was the first night I'd ever been completely on my own and the first time I'd had my own bedroom.
As adults we're not especially close now. We help each other out but wouldn't go out of the way to socialize. I am close to my sister who's the oldest but we live a long way from each other so rarely meet up.
I have friends from 2-4 children sized families who are all very close, I'm not sure if it's size so much as personality and family dynamics that affects how well you get on.
So I might recommend it for a child. Not sure if I'd recommend it for parents though. My folks rarely did anything together, never had any money and never went on holiday. They were happy in their relationship though. It's not the life I'd want for myself - so much to see and do!