Alienware 17 R1 Opinions

Hey guys I need your opinion. I used to own a M17xR3 which I loved, but eventually sold, and I am back on the market and am torn between the new and slimmer (but back to plastic) 2015 lineup and the aluminum AW 17 R1. Can anyone that has had the M17x R3 and the AW 17 R1 tell me how they compare size-wise? I did not have a problem with the size of the M17x R3 at all, but its hard to compare via pictures only. I'd like a firsthand account if possible.

Thanks!