I haven't used either, but I see good things about ZaReason, and I have been a little disappointed in my System76 Desktop (though I did heavily customize).
They come in a lot cheaper than those new MBPs, too
Configured approximately the same as the cheaper Retina MBP, the verix cost $200 more than the retina macbook pros.
I say approximately because the mbp has 1600MHz ram vs 1333 in the verix, but I had to choose a 300GB SSD in the verix vs 256 in the mbp. As well, the verix option was for a 2.2GHz vs 2.3GHz of the MBP.
That was the cheaper MBP. Configuring the verix to match the costlier Retina MBP puts the Verix at $500 more.
I neglected to consider the flash storage costs in my initial glances. If you avoid a large flash drive (I usually run something like a 40GB ssd and a 256GB 7200RPM paired), the pricing leans towards the Verix, but not by much - and you aren't getting the same flash storage.
Verix: Dimensions: 15.6" (w) x 10.5" (d) x 2.2" (h) Weight: 7.10 lbs
MBP: Dimensions: 14.13" (w) x 9.73" (d) x 0.71" (h) Weight: 4.46 lbs
With Apple you are stuck with very few yet pricey base configurations to start from.