Im using this on an old Compaq server with 500Mb RAM. I really like the concurrency feature - it makes a big difference. I did want to make a couple of points on the beta:
During boot process, I got the message: "xd: Out of memory". It still worked though. I dont think it used up all 500Mb. At the main menu, the menu items along the bottom didnt seem to all work. Specifically, M and V didnt do anything - not that Im really sure what they were supposed to do. Maybe I just missed it.  It would have been nice to specify some of the wipe parameters, like the number of passes. There may be nothing you can do about that, pending the release of wipe-2.3, but I thought Id mention it. The display was a bit off. I have 7 drives installed. Only five showed up in the list, but the last entry had 3 xfr-rate boxes. All drives seemed to be running. I think its just a display issue.CPU utilization display was off. After a few minutes it seemed to sort of stabilize between 760% and 801% utilization. Talk about overclocking!!  Could that be a decimal point thing? (ie. 76.0 and 80.1?)
Otherwise so far so good. Looking forward to v1.0.