So, I don't know much about the Asus ROG Strix Hero, but I know a lot about the Predator Helios 300, as I am tying this on it right now. So I'll tell you about the Helios and maybe that will help you decide.
This is far from a perfect laptop. However, for the price, the performance, and what it is, it is a great bargain.
The pluses on it are the performance, the ease of HDD/SSD and RAM upgrades, the backlit keyboard, the sizable touchpad, the ample amount of system and video RAM, and the price.
The minuses are the screen (which is nice, sharp, has great viewing angles, but is only 60 Hz and isn't suitable for being outside as it doesn't get very bright), the battery life (which I suppose is acceptable in a gaming laptop), the keyboard (it is a little mushy and is only red backlit).
Over all I'm extremely satisfied with my Helios 300. I use it in my office and travel with it and it works well. I even play VR games on it and it works well for that. I don't have any thermal problems with it what so ever.
Now, I notice that you have the version with the 2 TB HDD installed. I'd recommend not getting that one, and getting the base one with the 256 GB SSD and open drive day, then adding a reasonably sized SSD for game storage. It works REALLY well. It also costs less.
Now, the Strix Hero IS going to have a better screen, but it will cost more as a result. So there is a bit of a trade off there.
Hope that helps you make a decision.