When did you try the service? We've made a ton of changes over the past few months that have made things much more stable than they were during our beta period last year.

"(however I was under the impression this wasn't in their immediate lineup; making it easy for users to cancel isn't exactly good business sense right? *nudge - poke*"
The primary reason that we don't have an easy way to cancel is we don't want someone to take their site down by mistake. If we allowed people to easily delete a domain from CloudFlare, without the user first changing their nameservers back to their original registrar, it would cause major issues for the site owner.