as long as you don't need to mess with the lift springs on the door, i say install it yourself. i replaced both of our GDOs when the old ones died. takes maybe 30 minutes for a direct replacement, probably a couple hours if you are changing from chain to belt.

yeahI'd be changing from a chain to a belt PLUS adding the safety sensors on the door. I'm considering doing the new opener though, the one that goes on the side. Seem kind of neat, but also a pain in the arse as some people have mentioned.