I see a lot of discussion about Chamberlain vs Liftmaster, etc., but don't see anything about the differneces between the two Chamberlain models in my title. It looks to me that the only difference is that the RJ070 has MyQ bulit in and has battery backup. Is that true, and if I need battery backup down the road, can I add it to an RJ020 by purchasing a battery? There doesn't seem to be a lot fo advantage to the RJ070 for an over $200 price increase.

