Well, I got most of the parts installed and built up Wednesday morning, but ran into a SATA problem. First the RAID bios didn't see my SSDs at all, RAID or otherwise, even though the UEFI did. Saw the mechanical Seagates though. Had to pause it while I went to work, then resume Weds evening. Seemed to sort itself out with some cable jockeying between SATA ports. Have to remember that two of the SATA ports are controlled by an ASMedia chip and not the Z87, they'll support HDDs and optical disks, but no RAID support. The horizontal mounting is a bit of a pain, because they're directly under the GPU. At least with them being horizontal mount, you can plug stuff into them still. Its just a pain. Vertical mount SATA ports would be reduced to about 2 ports in this layout.
My experience in cable management also sucks, and there's a lot of tight runs and corners in the Define R4 case to route around and through, etc. To even do it, requires a lot of effort. Both side panels need to be off when routing cables, but when installing other parts in the access side, you'll want to pop that reverse panel back on so the cabling doesn't catch on anything. The power cables on the front fans also don't reach any of the Cha Fan headers on the main board in their default positioning either. Simple fix though, rotate the fan until the power cable is on the uppermost side instead of the lower side. They'll reach the case's connectors that connect them to the voltage switch on the front, but after trying that I decided I'd rather have them connected to the main board headers. There's more control that way, I can observe their RPMs and control them to a finer level then a 3 position voltage switch.
I'm in the process of migrating data from my old drives, which is going to take some time. Must remember though, with an SSD, a 150+ Windows Updates take about 30 minutes to download and install.
I might try some reworking of the sata cabling, by reversing the position of the drives, so the sata/power connects are facing the nonaccess side. This would give it a cleaner look and allow more airflow, but I'm not sure if the power cables would reach that fan.
WEI is 7.9 on Graphics and Gaming Graphics, 7.8 on HDD Transfer, and 7.6 on Process and RAM speed. Perhaps that'll go up a little in 4 or 5 months when I toss in some faster RAM. Current RAM is 16GB of DDR-1066. I plan to take that up to PC3-2400-ish, and double it to 32GB. Haven't run any benchmarks yet though.
With the stock Intel cooler and stock thermal paste, it idles between 38 and 40C. Bit warm, but not excessively so. I might pick up an after market cooler eventually.