Finally got time to play with these. Here is my mini-review.
The IPMI on these needs to be reset. Currently I use ipmitool on Linux to change the admin password so I can login and reset the configuration. Is there an alternate faster way? I also highly recommend upgrading the IPMI firmware on these.
The LSI SAS controller is already flashed to IT-mode, which is great. I've not taken the time to find out if it is the latest version.
Doing number crunching on these is not highly recommended. There is no air shroud included, which makes the current air cooling not very effective. Dual X5560 running 100% for some time will go over 90 degrees Celsius and may start to throttle. There are no issues using dual L5630 though, but that is expected as they use a lot less power, but they are also 30% slower. I would not run any six-cores on these.
This chassis is very quiet, not something you want right next to you. The PSU makes a high pitch noise though, but all is fine when you place it in another room.
Idle power usage with 1 CPU and one hard drive is around 85w.
Overall, great value for ~$120 incl shipping.