The X399 Aorus Xtreme takes things up a notch over last year's Gaming 7, and it's by and large succeeded in creating a better board that's a super attractive home for your Threadripper chip.
It looks good, performs well, and has just about every feature you'd need. Sure, I'd like to have seen a faster Wi-Fi chip and maybe RAM slots that are located further away from the CPU socket, but neither of these things are deal breakers.
At S$635, the X399 Aorus Xtreme is a lot cheaper than the S$969 ASUS ROG Zenith Extreme, while still offering a similar level of performance and feature set. The ROG Zenith Extreme is still the more feature-rich board, with support for VRM cooling add-ons and luxuries like 802.11ad WiGig and an OLED status display on the I/O shield, but these aren't really essential features.
The ASUS board also has support for 10 Gigabit Ethernet, but it does so through the ROG Areion PCIe add-on card. In comparison, the X399 Aorus Extreme offers 10 Gigabit support without any need for extra hardware, arguably a more elegant solution.
If you don't need the extra bells and whistles the ROG Zenith Extreme offers, the X399 Aorus Xtreme is shaping up to be an excellent choice for your Threadripper build.