In regards to my experience with 4H, here's some of the things I did and didn't like about it.
Sadly, I think my age group was deprived of agriculturally influenced kids. There were kids older and younger than me that had all their friends from their age group they already knew.. and yet I was the only one my age in my 4H horse group. That, along with the meetings that were very uninteresting to me at the time (they may have gotten better since... but it really seemed to be run twords the likings of the older kids, not really 'exciting' or what not for the younger ages..).
Another thing, but this isn't really classified in either good or bad.. Because it's a horse group, all the practice and skill work was done on our own. If your going to be in the groups, I recommend maybe finding out if others in the group would be interested in having 'get together practice/learning days'. I'm sure all the 4H groups have their own 'style' of doing things... but ours didn't have anything like this when I was in it. Plus, considering we only had once a month meetings, getting together a group like this wouldn't make it an impossible thing.. like it wouldn't make your life fifty times more hectic.
The whole '4H event day' experience is AMAZING. I still go to it every year to watch, and having 3 cousins (two 12 and one 11) who have been doing it, I love to help them out prior to and on show day. All the kids seem to love the process of it all. It's a pretty big and exciting day for them to say the least.
Horse Camp. Here we have a horse camp every year in June, where all the kids who want to participate from any of the horse groups get to stay over night at the fairgrounds, and stall their horse at the fair grounds. During camp, they get to take place in almost every main horse event, whether it be showmanship, trails, jumping (it's a basic how to... not much more than a log on the ground or a very simple cross bar... thing... lol. Sorry... idk what the term is... I've been a western person my whole life) etc. All the kids also get to tack up their own horses (older kids would help younger ones), clean up after them, and feed and water them. We also have really cool 'hands on' lunch time activities.. such as when I went we made pizza's from premade ingrediends... starting from a ball of dough, to cooking it on an open campfire. It was a blast.
One other thing... We had to give at least one demonstration for the year in front of the group... Which was a great way of learning new things from areas you aren't normally involved in. (we had a bunch of variety.. from horse stuff, to cow, chickens, pigs, rabbits, etc. Pretty much any demonstration teaching people something.)
Hmm... Yea. That was my 'highlights' of 4H. :) I'm sure all the clubs are different, but that's what I liked/disliked from my 4H experience.