I'm into my third year of the service, and I love it. It's great if you don't mind reading older stuff. I've been in 2007 stuff for a while now and encounter almost no gaps in the runs. Unfortunately, the more recent stuff is still littered with random gaps.
I can understand Marvel wanting to keep the books behind by about 6 months, but I wish they would post the books in order. These gaps are irritating me.