Minor gripes: (1) The dispayport-hdmi thing, (2) the mainboard is split (sound + rhs usb are on a separate board) and the small part has pretty flimsy attachement inside the case, (3) the CPU (i5 broadwell engineering sample) is pretty lackluster but perfect for development (no turbo, no throttling, no surprises), (4) finding an ok screen is hard, (5) nobody told me that I have to buy a separate wifi card. There is a free mini-pci slot, but 51nb could have been clearer on their online description, (5) the old x60 speakers suck.
Overall, it is an awesome machine (trackpoint, ibm keyboard, beautiful rubberized metal case). And shockingly cheap: An x62 mainboard, plus an old x60 chassis from ebay and battery from amazon, plus screen from alibaba, plus SSD, wifi-card and ram comes at ~$600 (I think?), cheap enough to buy as an experiment. I can definitely recommend to anyone who is ok with a little tinkering and the small adventure of ordering this from China (best approach: have Chinese colleague).
edit: Linux drivers work perfectly. Really, the ram was the most expensive component of this build. To expand on the no-surprises advantage of the CPU: To me it is more important to effortlessly benchmark small code changes than to quickly compile large codebases. And the weird engineering sample CPU that the 51nb guys sourced somewhere is absolutely perfect for that: Timings reliably match up with Agner Fog's instruction tables / iaca, without anything getting into the way (after the kernel cpufreq manager adjusted).