There used to be a time when AsRock split off from Asus and became the little brother that offered budget versions of Asus boards because cheaper manufacturing.
Then Asus closed all of their former plants, and started producing in the same plants as AsRock, but AsRock had about a 10 year experience advantage in using those production facilities.
Now AsRock is the new Asus and Asus is overpriced non-so-good stuff. Asus went from being the best mobo manufacturer to being a generic gadget rebrander in the last 6-7 years. Asus gave up on all of their promising products over the years, killed their after sales support to basically an answering service that only says "no" and "I don't know" to customers. It used to be my favourite brand, I hacked on the WL-HDD back in the day, all my laptops and mobos were Asus for years. About 10 years ago, they started having serious quality issues with their mobos and they started killing their most interesting products. After 2010, the laptops started to have serious quality issues. Now, I don't buy Asus any more because there is always something wrong with what I buy from them, and often it's not so nice stuff, like disabled functionality that is undocumented, BIOS settings that are useless or screwed up, faked functionality that doesn't really work in reality, etc...
I haven't had that yet with AsRock and Gigabyte. Both of these mobos have been working well, and especially AsRock has shown that they implement new functionality pretty well, so that it doesn't only look good on the box, but actually works in practice. Gigabyte has also delivered, albeit sometimes after several BIOS updates, but those were pretty quick in being released, unlike Asus, and they actually solved the problems, unlike Asus.
In short, the much denigrated split-off brand of Asus, AsRock, has taken the lead Asus once had in mobos in terms of quality, reliability and functionality. That is the way I have experienced it over the course of the last decade.
With this X99 board again (just noting that Fatality products are not just a premium price for the name, but actually often are a clever cocktail of functionality for a clever price), AsRock has come up with a product that offers a pretty solid board for the price, with lots of functionality and a good build quality. Some of the obvious mistakes on Asus boards, like bad positioning of chokes and caps or handicapping certain platform advantages, are not found on AsRock boards. I have a TaiChi X99 board in a working system, and it's performing great. The Asus WS boards I got last year, have been decimated from 3 to just 1 that's still hanging on, but is also starting to crash inexplicably sometimes. They will be substituted by AsRock or Gigabyte boards, but probably AsRock.
The only thing seriously lacking, is the ex works capability to use open source BIOS. That would really be nice.