Question regarding 144hz monitors and 1080p vs UHD

I want to order one of the new 27 in GSYNC 144hz monitors. I dont think i will be gaming above 1080p because i only have one GTX970. Should just get the 1080p model or the UHD version. If i get the UHD version, can i just game at 1080p for now and upgrade graphic card later in the future for the full UHD experience? I guess the question is will gaming at 1080p on the UHD look funny or be compromised in some way?

Yes it will screw image quality, it will look like blurry or washed out.

Just game at 2160p and lower your settings. Majority of games will run just fine with a GTX 970.

Those don't come in 144hz though. 60hz max until DisplayPort 1.3 starts showing it's face.