For those who are curious about more details, I ended up taking the plunge and ordered one of these from Superbiiz this week.
ASRock E3C226D2i
Xeon e3-1240v3 OEM
Kingston KVR1333D3E9SK2/16G DDR3-1333 16GB(2x 8GB) ECC Unregistered CL9
Scythe Big Shuriken v1 with full-size 120mm fan (SY1225SL12LM-P)
Seasonic SS-300SFD Power Supply
Lian Li PC-Q25 case
IBM BR10i SATA card
Plus a bunch of 2.5 and 3.5 hard drives
Overall, everything worked pretty well out of the box. The motherboard comes in a retail box with 6x SATA cables and, curiously, what appears to be a backplate for a CPU heatsink. The manual doesn't mention that part at all.
Idle power, ESXi 5.5 (CPU, RAM, and 3 fans at low rpm): 23W
Idle power, ESXi 5.5 (with RAID card and drives in standby): 40W
These idle power numbers are pretty similar to what I was getting with my i5-2390t, except this CPU has a broader "range" and is much snappier overall.
The whole IPMI function is new to me and looks pretty cool. I like being able to see the temperatures and fan speeds independent of whatever OS is running. You can even log in via ssh into a little BusyBox shell, which looks promising for some customization.
I did encounter some issues that people might want to know about:
1. The fan controls are pretty minimal. You can choose either manual or "SmartFan" for each of 3 fans. However, there's no ability to set thresholds, fan speed warnings, etc. The default profile seems to allow the CPU to get over 50C before it ramps up the fan speed. I'll probably submit a support request and see if they can add some more granular control in a future BIOS version (one can hope!) This may not be a big issue in a datacenter environment, but for a quiet home server I'd like to have a lot more control over the fans.
2. ESXi 5.1 is on the supported OS list. However, with a fresh install, something about the partitioning scheme causes the motherboard to lock up in a way that it won't boot when the drive is connected. Google 'runweasel formatwithmbr' for the workaround if you plan to use ESXi.
3. I had been using OpenMediaVault as my main OS with VirtualBox VMs, but the 2.6 kernel seems to not support the latest Haswell power saving features, so the system was idling over 60W. So, make sure whatever OS you run is running a relatively new kernel if this is a concern. ESXi 5.5 seems fine with Power Saving set to "Low Power".
4. The i210 network adapters are relatively new, so getting drivers can be a bit of a pain. However, Patrick has a nice
article that explains how to do this for ESXi.
5. I'm a little confused about the "dedicated IPMI interface" - the BIOS only allows you to configure management services on the two main i210 interfaces, and the manual is next to useless. Anyone have an idea how this is supposed to work?