IMHO, despite the powerful speaker and the comfortable keyboard by Lenovo, don't go for the Lenovo Y40-80 if you wanna do gaming most of the time. Currently, Radeon tech is far behind Nvidia. So, try to avoid Radeon graphic card.

Although the ROG comes with FHD and a newer graphic card, GTX950M has the almost the same performance as the GPU in the 7447 (GTX850M). On top of the quality build and design, both 7447 and ROG have some stylish designs but the ROG comes with plastic fabrication, some have given critics on the bad materials to build a gaming laptop.

If you can still manage to find the Dell 7447, don't hesitate and go for it. Quality build, powerful processor, decent graphic card performance and good after sales service from Dell.  The only drawback of getting the 7447 are the weight and also the VGA port. To some people, VGA port is very important but if I am not mistaken, Dell does give out the HDMI to VGA converter for free. And also since you are comparing between 7447 and ROG, both of them are heavy. So, go for the 7447.

Hope this less than impressive comparison helps a bit in your hunting process. Cheers.

You can pretty much ignore Asus if you want a good after sales service. Go for the Dell 7559. The price may hike at certain places but still a very reliable laptop. And importantly, it fulfills almost every single requirement of yours. It's gonna be worth it for sure.

PS: you can consider i5 for a cheaper price.
Dell 7559 i5. Use the remaining budget to upgrade M.2 slot to SSD