I can't speak for the other forums but we sure have a boat load of fun over on the iris forum! You never know what we are going to be up to. One thing is for sure, if you are having a problem, need advise, are in search of a certain cultivar or whatever the case may be, you will not find a more helpful group of people anywhere.
I have made some very dear friends there, and learned a lot too.

ATP is also a valuable resource for all of your other gardening/plant needs. There is someone always willing to help solve your problems and answer your questions.