Good question. I am sure everyone will have a positive opinion either way. Personally I prefer the dual boot option (mainly to get rid of headaches with compatibility and networking issues.) Also with my setup I actually VM windows with Kali, though on my desktop I use Windows for gaming (which may change the way it seems how Steam is evolving lol).
However it really depends on your preferences. Once you get everything running smoothly you will be happy with either choice. With Dual boot benefits are: Mostly everything works out of the box, or at least no more than the usual hoops you have to jump through to get everything working. You have full access to all your hardware.
Cons: Must reboot your machine to get back into windows. Windows does not natively recognize your Linux partition. Full Disk Encryption can be a pain to get running correctly.
Benefits of VM: No rebooting. Setting a bridge to share files between the OS's is easier. Can use full disk encryption like truecrypt without any issues. No need to partition your hard drive.
Cons: Not always easy to tell if a problem is related to you virtualizing Kali or another issue. A lot of hard ware is virtualized, like video card (meaning some perks will not be fully utilized). Internet issues might arise between different tools.
With that said, I prefer Dual Booting, for its ease. However I must point out from your system spcs, you shouldn't have any issue with VM.