Thanks again for the benchmarks and the updated information! Im honestly still on the fence on upgrading to the newer model. As most of you know either by my posts or from my signature, I have the Early 2013 rMBP with the 2.7 Quad Core i7 Ivy Bridge, 16GB RAM, and 512 SATA SSD. I honestly haven't had any complaints from this machine whatsoever but of course would like more GPU horsepower when playing games. Like i mentioned before, I only play WoW, but I do run WoW at 2880x1800 on low settings except for visual foreground which is set to medium so I can get some distance factor and it runs great and looks great but would simply love to crank it up to high or Ultra even on 2880x1800. I am unsure if this new GPU will be able to run Ultra 2880x1800 at 30+ FPS consistently. If I can find someone that could run that test and prove to me, I would upgrade in a heartbeat.
I don't think it makes much sense for you to upgrade. The new laptop is not that much better.