Hello! I am a GS65 owner!
Yes, the GS65 produce lot of heat. But it can be managed. Now I'm testing some undervolt settings, and the laptop is really better.
I'm playing with Heroes Of The Storm, who's cpu intensive, Magic Arena, and some Indie Steam game. So, not, I'm not playing hard with it.
I tryed Black Desert Online too, before undervolt, and the fans goes spinning like hell!
If the machine will last overtime.. I really dont know. I purchased a 3 years extension indeed.
About built quality... it's not so bad. I think the display is a little frail...