i own the g751jy. i will list some pros and cons of it that i have found so far i previously owned a g75vx. i upgraded to a 1tb ssd and thats another story i will explain

Pros

Power and cooling:
its very powerful and very quiet. and the cooling is some of the best that i have ever seen and used also the quietest. when running a stress test a very intensive one i got my cpu temp up to 91c before i shut off the benchmark to be safe. it was starting to completely slow down so i doubt it would have gotten warmer than 92c. the gpu was a little cooler around 86 area. the palm rests and keyboard area don't seem to get warm at all so if you game on the internal touchpad and keyboard your hands aren't going to melt off 😛

Display:
the ips panel is a major step up from me from the tn panel on my older g75vx. crisp and clear images and its a matte finish so its good in bright rooms too. a little issue i have been having but this may be due to the fact im on windows 7. is that after i sleep the laptop the brightness controls no longer work and i have to restart the computer to regain the control.

Hard drives/ ram:
im pretty sure all 3 of the laptops in the g751 lineup have dual 2.5 inch sata drive bays a m.2 slot and 4 so dimm ram slots. the g751jy i have same with 24 gigs of ram split between the 4 ram slots. it also had a m,2 ssd 256gb and a 1tb 7200rpm hdd. the m.2 drive slot is in the same area as the 2nd 2.5 inch drive bay so you have to choose between m.2 or a sata drive. also keep in mind if you plan to get a 2.5 inch drive for the laptops with the m.2 ssd you wont have a drive caddy to hold the 2.5 inch drive. you will need to purchace one. (or in my case i modded one from another laptop to work

Performance in game:
my model has the i7 4710hq with the gtx 980m so most games tend to run at ultra and 60 fps. and a lot of games really aren't too taxing of the machiene. i can easily game with it on my lap (on bare legs) and have no issues becoming uncomfortable from heat coming from the laptop. i have also never experienced thermal throttling.

Battery:
unfortunately the battery in the g751jy is not removable however when now gaming and even when on high performance on battery i can usually easily get over 2 hours of battery time when browsing the internet and watching hd videos.

I0 (usb ports etc):
this computer is stacked pretty good in terms of the i0 it offers. it has 4 usb 3.0 ss ports and one of the is a faster charging one for apple devices. it has a thunderbolt, hdmi and a vga port. it also had a blue ray reader and writer drive. it also has 3 audio ports. 2 headphone/ speaker outputs and one mic in/subwoofer out.

Sound:
the internal 2.1 speaker system is actually very impressive in terms of sound quality and output. and the interfaces seem to work good within the computer.

Cons:

Now for a couple of cons/ issues and things i've done to fix them and also ones i haven't been able to fix as of today.

Mouse drivers are terrible:
me bring a gamer that is on the road often i usually use the touchpad and the keyboard build into the computer. however the terrible elantech driver doesn't allow you to use both of the touchpad buttons at the same time. and it also had this weird issue where it would randomly stick around places and it would take a second to respond (clearly ruining gaming). What i did to solve this is i downloaded and installed synaptics touchpad drivers. unfortunatly you will lose the 2 finger scroll and pinch zoom. basically the computer recognizes your tpouchpad as a ps/2 mouse and not a touchpad so you wont have any gestures but the mouse will work good and both keys can be used at the same time.

Display brightness:
as i said before in this post if i put my computer to sleep and wake it up i lose the brightness control functionality until restart. i have tried everything to remedy this with no luck and i have a good feeling its due to the windows 7 install on this pc.

No windows 7 driver support from asus:
if your want 7 its up to you to make it work in terms of drivers. i found the majority of drivers worked properly that were meant for 8.1 except for sound, i am guessing the atk package, the 5 hotkeys i couldn't get to work either or the asus manager. the 8.1 sound driver works but the asus audio wizard has a glitch where it defults headphones and speakers to small. to fix that i used the g750 audio drivers for windows 8. i haven't found any solutions for the other issues so far.

Conclusion:
overall i love this laptop its a powerhouse with amazing cooling and is almost silent. very pretty display i love the internal keyboard. i would avoid installing windows 7 unless you know what your doing and you really want it. i had to change some boot options in the bios to be able to run 7 (not very hard) and the build quality on this laptop is amazing.

I hope this helps, any questions feel free to ask