First things first. This is not meant to be a thread to bash the rMBP so please don't jump down my throat. The rMBP is a very very nice machine. The screen is by far the best I've seen, it's quick, and has a beautiful form factor. With all that being said, I had UI lag and couldn't overcome it. This was on a 2.7 i7 with 16 gb ram, and 256 SSD. I tried but couldn't make it work. Back it went to the apple store... Now i'm sure not all rMBP are experiencing lag like I did, but judging by the amount of posts I've read it does exist. I didn't have image retention even with the LG screen. I truly wanted to like the retina, and in many ways I did. It is a fantastic piece of kit. Maybe the lag I experienced is hardware related, maybe software, but I couldn't take the chance that it may or may not get fixed. Here's hoping by the time I'm ready to upgrade next time, retina's will be in full force, more apps will be optimized and the hardware will catch up to that gorgeous screen! Initially I told myself no way I buy the cMBP because i'd feel like I was buying an "outdated" computer so to speak. However, I wound up taking the plunge and it is absolutely fantastic. I bought the 2.7 i7 model with 8gb of ram and a crappy 5400 1tb HDD that I will be replacing with a Samsung 830/840 pro. Even though I'm using it stock this thing is still quick. I can only imagine how it will fly once i upgrade the ram and put in an SSD. I'm excited to say the least. Again, this isn't meant to bash the retina model. I hope those of you using it are enjoying it the way I had hoped to. I just wanted to show a little love for all of us classic owners. Maybe this model will be going by the waste side soon enough, but it is a refined product, tried and true, and works like a champ for me.