By the time next year's update rolls along, something even better will be on the horizon. If you keep waiting for something better you'll never get anything.
That's true, of course, but some yearly revisions have more oomph than others.
For the OP, there are a couple important factors to consider here. First, the first-gen rMBP does seem to have a few issues (as is common with first-gen devices). Second, you need to think about what's coming next year. Haswell should be a huge upgrade in both battery life and graphics. Since an update is only 8 months away, give or take, I'd say hold out unless you actually NEED one right now.