I go with a little intervalometer for my Canon - it cost about $40 and so far (
) has been completely reliable. It also uses almost no battery power (batteries last a very long time indeed), so it's one less thing to worry on power drain. The downside is perhaps as much about no having instant access to frames as they are taken - so to check a frame I have to stop between exposures, check the preview, then recheck the guiding, then start imaging again. Upside is that it's really easy, and you can set it to do a bunch of darks after you go to bed!
But I'm tempted to try the Backyard EOS...