I can't help you in comparing those specific two boards - I have the X99 E-WS. That said, hopefully this is of some use.
Apparently a lot of people have had problems with the Asus X99s, but I'm not one of them. It is one of the best motherboards I've used in the Intel world. Hardware-wise, this machine has an E5-1650v3, 64G Crucial ECC RAM, a GTX 970 and a Quadro K4000, a Samsung 950 Pro M.2, 4 WD greens, 2 SSDs that were laying around (forget which brand), powered with a Corsair AX1500i PSU. It is air-cooled, with plenty of fan and a CPU heat tower in a big case, and the cooling was more than fine in a stress test. (Yes, the PSU is way-overspec'ed. I tend to swap around hardware, and I got that with an eye towards possibly later using it in a large storage array that will be built next year.)
I run Ubuntu 16.04 and Win10 in a VM, mostly for industrial design. After the usual annoyances in setting up sorta bleeding-edge stuff like VGA-passthrough, this machine has been flawless on the hardware side. (Some software hassles, and in particular, Nvidia doesn't like VGA-passthrough and keeps crapping-up the drivers, requiring increasingly annoying workarounds - if you want to run VGA-passthrough, I recommend that you not buy Nvidia. Difficult decision if you are running pro apps, and the fallback is to dual-boot, but I really hate managing windows, and like to just be able to restore a snapshot when something goes wrong with it. But that's not about the motherboard. In conclusion, Nvidia can bite me.)
Again, I have to say this is one of the best motherboards for X64 that I've owned. I'm not overclocking - running ECC, don't do games, and care about stability over that last 1% performance. But performance has been excellent, it is extremely configurable, I've had no issues with stability or bugs I can trace back to the hardware.
A note about IO performance - this box actually has four tiers of storage speed (M.2, SATA SSD, 4 disk ZFS RAIDZ1, and gig-e NFS to a file server cluster), it is amazingly noticeable which one you're using when doing heavy IO. Everything else is so fast, even under load, that you'd immediately notice which you're writing to even if you didn't set the box up.
It looks like you're building a graphic design workstation, so multiple processors are not worth the expense (Resolve will be GPU-bound, only parts of Adobe CC apps can use multiple cores), so one of these boards would be in the high end of your options. 10G would likely be very useful, if you have the switch and storage on the other side of it. I'd highly recommend checking the hardware against the Asus documentation; it seems like the problems some folks have had with these boards is about hardware compatibility.
Another option would be to look at Supermicro. Some people don't like that they don't feel very polished, but if you don't care about that, they make great boards. I don't currently have one that compares to the Asus X99s (I do have an X10SDV-TLN4F in a storage server, and it is excellent), but they'd be worth checking out.