Title says it all, so take this for what its worth...
Built a machine about a month ago using the P6X58-E WS motherboard. Looks solid, no real issues identified. Specifically, it correctly allowed the use of a 2.4GHz Xeon 5645 with 12GB of ECC DDR3 clocked at 1333. SSD and 4 other SATA3 HDD all installed without issue.
I opted to overclock it a bit to 3.1GHz, with (good) air cooling, and careful attention to case airflow. Temps have been very acceptable. No flakiness to any parts, no reboots / hangs etc. The overclocked machine was proven Memtest and CPUburn stable.
My one "regret" with this board came after I was tweaking the setup...it *IS* correctly mentioned in the motherboard manual, but I had not read all the fine print. Specifically, the SATA2(x6) and SATA3(x2) ports all support RAID in one form or another. However, with the SATA2 bank - if you want to set them up into a RAID array, its all of them or none of them. In my case, I was originally hoping to put 2 of the "spinners" into a RAID 1 array, and leaving the other 2 drives as solitary scratch disks. Apparently, this is not possible. As a result, with the SSD drive correctly on the SATA3 port (drive supports SATA3), I can't configure my drives as originally planned. There are lots of ways around this, or course, but the relative inflexibility of the configuration (apparently a chipset limitation) caught me a bit off guard.
Otherwise, the board seems to be working great.
Again, says nothing about the PRO...
-A