I'm an associate member, I don't ride there but I teach on occasion.
I've actually just moved, so I am going to be trying out a new pony club. I've been to three others before and they're all very different, its interesting that clubs can have the same written policies and such, but all have such a different flavour.
My first one (my favourite of course!) was the one that I grew up with, and we were very focussed on eventing, with usually each rally day incorporating some dressage, show jumping and cross country, and then often some mounted games or sporting.
The second club was more just about riding around. The third was very into showing and sporting, with a little jumping. Pretty much whatever you'd do at a gymkhana. But they were much more into troop drill and stuff, which the first two never did!
I think Pony Club is great. Sure the quality of teaching can vary, and the it can get a bit petty, but you pay, what, $60 a year for probably 30-40 hours of instruction! You have the opportunity to learn so many new things and try things out. It's a great place especially for farm kids and such whose parents won't fork out for lessons, or people new to the horse world who need to learn about horse care.