The Omen has a slightly better dedicated GPU, click here .
Seems that particular Omen is out of stock except on HP's site at £899. The ASUS is a lot cheaper but the graphics is lower. It looks as if you need to fork out for the NVIDIA® GeForce® GTX 965M card if you want it. Good luck.
For Gaming in my opinion you should go for a ergonomic computer. with good keyboard/joystick design not just the one size fits all designs. As far as eyes , neck are concerned there are these newly designed monitor stands. Google them and you will find many. For reference one of them is click here, to give you an idea.
This thread is now locked and can not be replied to.