I personally really like taking Taggart to the dog park and he gets great enjoyment out of it too. I agree it depends on the dog though.
Taggart spends most of his time running and enjoying being off leash - that's the main reason I bring him there, because he gets such a rush from just running and that's the only place he can do that
He also seems to really like greeting every single dog and person there and that's most definitely helped with him not getting overly excited when we meet dogs on our regular walks because meeting dogs is less of a big deal when he gets to interact with them on a regular basis.

I wouldn't worry too much about the growling. The majority of dogs growl while playing and that's normal. Look at the complete body language and it shouldn't be difficult to see if it's play or not - if the body is stiff and there is growling, it means "back off". Growling while "wrestling" is just play-growling.
I personally don't intervene that much when Taggart hangs out with other dogs because he's good at speaking his own language and if a dog growls at him and tells him to get lost, he will do so.