Have you seen the XPS 13 or the Thinkpad Yoga? They're both pretty compelling laptops, and easily stand out from the crowded mass of plastic junk notebooks.
I just don't see any reason to pay $1,000+ for a PC Ultrabook that invariably falls short of an MBP Retina in some core compatency. For example, both machines you mention are $1,000+, have HD 4400 graphics versus the MBP's IRIS Pro, and have substantially worse touchpads (I never use an external mouse). The XPS 13 doesn't have a high-DPI display, and the Yoga 2 Pro has dramatically lower battery life (5.5 hours of web browsing on notebookcheck's review versus 9.5 hours; 6.5 hours of streaming video versus 11 hours on Engadget's review).
Surface Pro 3 probably won't measure up to an MBP Retina in terms of battery life, and the touchpad on the Type Cover is atrocious, but at least it offers something the MBP doesn't: a great form-factor for touch + pen support. If you can't execute a traditional notebook as well as Apple, you can at least try to execute something else.
The Yoga line is quite nice, and Lenovo seems to have wised up and simplified their SKUs (IIRC there used to be over 5 lines of laptops called "Yoga").
I have a Yoga 2 Pro, I love this high DPI 3200x1600 screen. It is amazing to read on, to the point I am willing to put up with a million other small compromises.
But I'd really love it if it had a TPM chip (it has Pro in its name, it should!) or a real digitizer. A Wacom Digitizer on a 3200x1600 screen? Drawing would be beautiful.
The Yoga 2 Pro was 999 when I bought it, although the price seems to have gone up by a fair bit. Also they had supply issues (now apparently resolved, Orange was on a month back order when I was looking to buy!)
The Surface 3 is actually almost a perfect replacement for this machine. The resolution isn't quite as nice, but it is thinner and almost as powerful. (The 4GB of RAM thing is not good, 8GB is almost a minimum just for heavy web browsing these days...)
Asus also makes some really nice hardware. Their ultrabook line is amazing, I am sad that they messed up their marketing of their one ultrabook a couple years back that had a discrete GPU in it. (It was only available through Amazon!!)
The reason tablets appeal to me is that a large part of my time is spent on reading technical books and documents, and in those times I really want the keyboard to just go away. The Surface Pro 3 has the screen size I was dreaming about on a tablet and it seems like a tablet you can use for work, and not just for play.
The one thing that disappointed me was 8GB upper bound on RAM. These things should really start at 8GB and go up to 16GB nowdays.
I am not too impressed by the XPS 13. But the Thinkpad Yoga and the Yoga 2 Pro are actually amazing machines (the later one has an even higher-than-retina display resolution. But again that is Lenovo and the PC world kinda need another player in the competition.
