Originally I'd decided on the pro, it has asus's own ram disk utility and it's cheaper by a long way. But in the end I went for the RIVE. This board gave me the best memory option, the 64gb gskill 2400mhz, the highest certified 64gb memory kit for x79 I could find (and tested on the 3930k). The pro is only gong to get you up to 2133mhz. Other than that I had no other reason to choose the board.
Ripjaws Z's are considered better than dominator's for x79, by people who know far more than me. Plus they're a lot cheaper than the dominator platinum (what isn't).
If your not a speed freak and are happy with 32gb, many really good options are open to you. Samsung green's Samsung Green (MV-3V4G3D/US) 8GB (2x4GB) DDR3 PC3-12800C11 1600MHz 30nm are great performers, thier low voltage (staringt at 1.35v! I think) is ideally suited to the 39xx and they can get upto 2133mhz. If only they'd done them in 8gb modules (they do for EC) heyho... They are a fraction (tiny) of the cost of dominators.
As you are overclocking 2133mhz memory should allow for 4.5ghzish, and the RIVE board will definitely serve you better for oc's.
What you should really keep in mind what you are going to use your machine for. Check your requirements. The 39xx's max memory bandwidth is 50GB/s, do you need it? Will the applications you want to use be able to utilise all 6 cores of the 39xx's; is your app cpu or gpu intensiveness?
It may be better to put your money to use elsewhere.
By the by: intel admits to no 'haswell E' or 'X99' . Who knows when a truly new 'performance' cpu will be delivered, if ever. Intel and AMD seem to be abandoning the shrinking CPU desktop market for the growing SOC market for tablets and fablets. We, and applications, will just have to adapt.