I've been meaning to try them for a while now, but just had the chance to purchase one a few weeks ago. So far, I'm loving it.
Among other things, here's what I enjoy presently:
* They sell large screen models (17.3", here). * The hardware is completely linux-compatible. I installed ubuntu fresh (just to check hardware compatibility out of the box), and had 0 issues getting __all__ hardware components working (primary SSD drive, wifi, nVidia card, webcam, mic, etc.) * Their laptop has a really sturdy feel to it and looks very 'clean'. They use beautiful metalic casing which makes it look really high-quality. * They have one of those really sturdy 'programmer' type keyboards that I love to type on. Big win. * Their hardware upgrade option are, in my opinion, excellent. I purchased a 120G SSD primary drive, and 8G of RAM, and this thing is insanely fast. I'm talking 2 second boot time, insta-opening of even large applications (K3B, I'm looking at you), and quiet operation.
Furthermore, their screens are absolutely beautiful. I'm not sure what distinguishes it from the $1,000 laptops you see around most stores, but the screen itself is top-notch.
As a side note, I use a laptop as my primary computing device--programming / movies / etc., and only run linux. I enjoy high-resolution laptops (like the one I purchased from system76), as I can have more vim-splits open :)
NOTE: I'm actually in the process of writing a full review on my blog about this laptop at some point in the near future.