Word I've seen over the past few years tells me Asus has taken a tumble in quality, esp with things BIOS related.
The components used to make them are still good to top quality, the noted issue(s) are it's almost like they forgot how to write a good, bug-free BIOS file - Similar thing Gigabyte has going on in the days of AM3/AM3+ with their BIOS woes.
ASRock has come up in quality and performance, no question of it and even MSI has made strides in the right direction it seems, at least there haven't been any reports of rampant VRM death going around as of late (With AM4) which is a good thing. Gigabyte from what I can tell is getting better, they still have work to do but better is better at least.
The MSI MEG ACE board I have seems good and the BIOS itself (Once you figure out the nomenclature) is actually pretty good itself.
Personal result from mine: https://hwbot.org/submission/4285521_
I have seen others say the newest BIOS files killed off performance a little for the ACE as an example and will say if it's something security related or to fix functionality/support issues I'd do the BIOS update.
However as long as neither of the previous applies I'd leave it alone and enjoy the board - And that's for any board make/model.
I currently have a X470 Tachi Ultimate (Daily) and the ACE for now as my AM4 benching board.
The above is simply what I've observed from my singular viewpoint since Socket AM4 was released and a personal take on all that.
Doesn't mean it's actually "Right", just an observation here and only applies to AMD boards with Intel based boards being a different matter.
If I had to choose a board today I'd go ASRock first, MSI second, Asus and Gigabyte being a tossup for third.
If anyone else has had a different experience with theirs, speak up please and let us (And the OP) know!