In light of the coupons not working (removed by author?), and Magic Member affiliates not being notified, etc... maybe it's not such a good choice anymore. An open source or free product with multiple developers might be more stable.
I found this review article listing quite a few.
http://winkpress.com/membership-plugin/
Maybe S2Member is the right one to go with. I'd hate to get stuck with Magic Member if it has a flaky developer, and then this time next year it's gone.