I can speak from experience with the DFI P35 LP Dark T2RS, great board, OC's like a champ, has the same BIOS settings as the lower-end Bloodiron. What makes the BI stand out even to this day is the budget OC-ability it provides...iirc it had a 4-pin cpu power plug, which can support Quad OC's fine from what I've heard...I preferred the better layout, extra cooling, 8-pin CPU power of the DARK, plus at the time I got my P35 DK I had just gotten my RMA Refund for an old failed (4th one iirc) Asus P5B Deluxe from newegg. At the time the BloodIrons were not in stock anywhere due to chinese newyear or something along those lines and very few P35 DK's were, I found a decent deal on a DK and snatched it up.
Some things I noticed, naturally I could OC a dual core further with less work, same with oc-ing 2 DIMMS of RAM over 4 DIMMS of RAM...anyone can tout good or bad results in here, the reality is that the milage will vary between components, power sources, cooling, Bios revisions, settings you do or don't mess with and so forth.
I'm very happy with my DFI DK P35, it's treated me quite well...given me some headaches when I was trying to OC a quad and 4x1GB of G.Skill HZ's, but I even got that sorted to an extent after a bit. I also like the fact both boards have a Clear CMOS jumper on the back I/O section, that's just kickass.