I have helped desperate head-fi'ers getting rid of RockBox - also the latest version and also very recently. This however, has been 60x models I should add. Personally I am never going back to RB because of my own disastrous experience with RB on my 801. I did manage to "resurrect" it, but never ever RockBox for me again. Concider yourself warned.
With RB you can play hi res files, yes, but they will be down scaled to CD format (44.1kHz/16 bit). Gapless is of course nice, but I have joined my classical multitrack files into one file for the 801 and then they are played "gapless".
Lars, from time to time I get in touch with the developer of the rockbox port for HiFIMAN devices. BTW he lives in Moscow. I asure you that Rockbox works fine on HM-801 for already more than a year. Don't mislead fellow headfiers plz. The only real problem is with the dislays of the new batches of slims and even not all of them. I don't know anybody in Russia, who has even a slightest problem with Rockbox on HM-801, and there are plenty of 801 users here.
So don't be afraid, ianmedium. Everything works just fine.
Edited by HungryDaze - 4/6/13 at 1:22pm