Seems nice so far.
Just installed Team Fortress 2 and it seemed to run ok other than not being able to select a resolution higher than 1280x800 for some reason.
Trackpad is a little lighter to push down on than my previous mac (2011 air), the 128GB might be a little limiting but there was no way I was going to pay an extra £200 for the 256GB ssd model, can always get a 1TB usb3 drive if i need extra storage.
Be interesting to see how well games run on it, don't plan to do any heavy gaming on it (Tend to use my desktop for playing PC games) but if it saves me lugging my old XPS17 (L702x) with me when visiting friends then I'll be happy as that thing is a brick.
Interestingly the Passmark G3D score for the Iris 5100 isn't massively lower than the one for the 555M in the dell, not seen may benchmarks for the 6100 yet.
Also is it possible to do download/extract the bootcamp drivers and have they got one for the new touchpad yet?
I might try seeing if windows can be booted/run off external media (It's supposedly possible with 8/8.1, and USB3 should be fast enough for it)