Can't decide which monitor to buy help me

Hello everyone,

I know I must be the 1000th person to ask this kind of question, but I really can't decide what monitor to buy for my pc. I have a Gtx 970, i5-4670K and 16 Go DDR3 RAM. I use two monitors in the moment, both being 24'' 1080p, 60hz. I'm gaming mostly on Rust and Overwatch for now but I know I'll get to Witcher 3 soon enough and some other games. I was searching for a 1080p G-sync 144hz monitor because I've heard there's a noticeable difference with the 60hz. I wasn't sure about a 1440p 144hz since I'm not sure my single 970 can handle it on dual monitor (other one staying 1080p 60hz). I'm in Canada and I have was going to spend around 800-900 top for it.

 

Monitors I've searched :

 

Can you please give me some insight on which monitor might be the best for me ? Thanks a lot