Hmm, well just to let you know, I have been part of many writers groups---on-line and off-line, through the mail ones, and ones through collages---they all have the same trouble.The members fall by the side, realize they can't keep up, think they are better than all the others in the group so quit in a huff, don't have the commitment to writing that the others do---on and on and on ect.
Take Critters, you can jump right in--do X number of crits per week and get crits in return. Sorta works. But if you write novels it does not work so well. People shy away from the novels there and you will only collect a few crits for several weeks worth of ones you do.
Del Rey-- you do crits in exchange for getting crits. They use a submission rating system that does work well---with an exception you get crits that are trash simply because that person wanted points toward earning crits. One thing they are good at though is responding if you complain about a useless crit.
Coffee House for Writers. Whoa, hard to get in. Pro writers group where you must be a published writer (earning $$ from your writing) and you must pass a screening by the moderators to get in. They expect several in depth crits per week---and they rip you to shreds. Not for the faint at heart.
I could list several others----but
The only way for a group to work is for all members to be committed to their writing and be willing to take the time it takes to do a good job.
No group or moderator can make people crit. And you will find that even some seemingly good members fall to the side when life gets in the way.
I'm a die hard and the group I was in here that continues after a year outside here---well I was the hard-assed obsessed-writer who kept after the core members about not taking time off, and meeting your sub date and crit deadlines. I was not well liked, and I don't think I am at times even now.
Crit groups are a good study in what it's like to find a publisher or agent---the match has to be right or it does not work.
Our group has kept the same four core members and has gone through a host of others. And even though I am not in a group here anymore---this one works well because of the structure of the groups, small and Kathleen does a good job of trying to match members to each other.
Good luck.
Shawn