I think it's really a coin flip. IMO the next rMBP-15 will likely be the keeper so I bought a 2011 cMBP-15 last week to wait it out. I think I bought it cheaply enough that I can wait and not take a depreciation hit, but still get a HUGE performance & feature step up from my old C2D wMB-13. But in your case, if you can swap both out even, you're likely to take the same depreciation hit if you want to flip into a Haswell rMBP in a year or two. So I would probably go for it.