As Barton George suggested here:
The preliminary results shown here look very promising:
I should buy today a Precision M3800 with Ubuntu preinstalled if it was available. And you?
I would really love to have this system pre-installed with Ubuntu and be officially a part of the Sputnik project. Either the XPS 15/M3800 would be great (as far as I can tell they are pretty much identical, but with a few internal hardware differences). It might be worth waiting until 14.04 comes out though, since 12.04 as pointed out in the article does not support some of the hardware in the system (not yet at least), but I also don't think it will be able to take advantage of the higher resolution screen as well either. Since Ubuntu is also developing their mobile OS (Ubuntu Touch) there will probably be more work on making it resolution independent, and I imagine some of that might be in 14.04.
I have a lot of interest in the M3800 (or XPS 15) + Ubuntu (both Haswell).
I don't know why Dell does not sell the XPS 15 Haswell (do they think we are stupid enough to buy the old processor ?).
I do not want to use Windows and I don't want to risk my money running Ubuntu because nobody can tell me (or does not want to) if the resolution of QHD+ (3 200 x 1 880) will not make everything too small... I don't want to use a magnifier glass ! :-)