Be patient and wait RV10THE. X99-E 10G WS is great but I would recommend that board for someone who no time for gaming and use CPU for rendering and few GPUs.
RV10THE is gaming/overclocking motherboard and better for someone who is more oriented for entertainment, fun, gaming, benchmark tests, etc...
But comparing look and functions I would choose RV10E without doubt before any WS board now.
I expect big demand for RV10E Black, on all sides I see only positive comments and silence from other manufacturers and their fans.
😄This hardware when no one can't say This is not good, some other board have better this, better that... RV10E first than one place empty than other boards.
I must say that most of people will be satisfied with ASUS X99 Strix. For 300$ they get really great board but Rampage series is story for self.