I've been following this as I have high hopes.
I've tried a few raspberry pi competitors over the years and they all look amazing on paper, but they're often not very useful in practice because of limited software support. They're often use proprietary graphics cars and other bits that have poor linux kernel support so you're stuck with whatever support the manufacturer gives you. I'm still steamed that ODroid end-of-lifed a few boards before actually fixing most of my hardware support problems with them. These problems become especially acute if you need these boxes to do anything graphical or audio related (as opposed to just being a headless server somewhere).
The reason the raspberry pi has done so well is because there's a huge community supporting it and it's a stable platform. Unlike some competing SBC's the pi's hardware support just keeps getting better year after year and they've almost got a completely open graphics driver which would allow you to run one entirely from the mainline kernel which would effectively ensure indefinite support.
There are very few other SBC's in the space that come anywhere close to having that kind of support, mostly because they're either: 1) produced by small companies with fairly limited resources, 2) or are targeting an industrial market (where graphics and sound aren't really important)
I'm excited that a big hardware manufacturer like Asus is entering the space, as they have a strong motherboard business and can wrangle hardware vendors. They have the resources to actually make it more likely their board will get decent support if they sell any at all. Everyone is complaining that the price is twice that of an Odroid C2 for similar specs, but people are discounting how miserable Odroid's software support has historically been. If it actually works (and keeps working), it'll be worth the price.