I finally finished the 5 movie obligation, after 1.5 years, and I had all intents to cancel, but wow, the deals! Once you're done with the obligation, you become a "VIP".
The key, IMO, to being happy with the obligation is to order them as fast as you can. Otherwise the incredible deal you got on those first movies gets forgotten, and you start looking at the cost of the movie plus shipping compared to the cost of it at Costco or
Amazon or wherever else. That's what happened with us, and what FINALLY got me to buy the last movie was finding something I didn't see anywhere else, not even Amazon (special version of Lilo and Stitch in a tin box).
You can send in the paper form that comes every 3+ weeks, you can reply to the email they send (for me they send the email a couple days after I get the mail, and to reply you log in to your account and either order or decline the current offering, then they send you a confirmation email about it a few hours later), or you can set a computer calendar up to check every week or so to make sure you haven't missed a mailing or emailing.
Although I goofed once with a Scholastic book club and got an unwanted mailing, I haven't yet with DMC (was a day away from goofing though once), and I've enjoyed it.
AND I joined through sunshine rewards and it successfully credited, so I got SR credits along with getting good deals on the movies.