chiefie: With that budget, you'd be wiser to go with G-sync monitors of higher resolution (4k) if your GPU can handle it And it will be more beneficial for playing MMO. I know I would appreciate bigger resolution so I can spread my HUDs out a bit more (I play FFXIV).
Just a note, G-Sync only works with Nvidia cards. If you have an AMD you need a FreeSync monitor (and only specific models of the Radeon work with FreeSync).
And just in case its not obvious, G-Sync/Freesync monitors dont come in the 40" size. They come in 24-27 (and maybe in 30").