My experience with them is exactly what's been in the news recently, they will try their best to substantiate a claim that they don't HAVE to fix your issue, if they find it they will definitely use it as an argument to deny your warranty but if they don't, it's smooth sailing. I've had many products from Asus over the years (and BTW I'm in Brazil) and actually a large amount of them had issues, a few had warranty left and I did have 2 warranty claims denied from them, a few years ago I decided to avoid Asus products after buying two identical phones from them that had the same issue that they themselves told me it was a known factory defect from those models and the.They denied service on one of the units, asking me to pay over the price of it to fix it because of an unrelated damage.
It really seems to be what Asus HQ instructs all Asus entities around the globe to do.
So yeah mileage will vary depending on your luck of who gets your product to review, and if they find any reason to make an argument against your warranty claim or not.