Waiting's worth it, for when Freesync comes out in 2015. Changing to Nvidia and a G-Sync display will cost you an arm and a leg, so the option to do something with VSync improvements right now isn't a good one.
Freesync gaming screens are going to be 144Hz TN panels though, and even though the G-Sync Asus is very good for a TN, it still suffers from vertical colour inversions and gamma shifts and it's still technically 6-bit technology which means that full colour comes from dithering. TR's review gallery clearly shows that the best-in-class ASUS suffers the same old TN-panel fate, even if it's the best example of TN so far - it's still TN.
If you don't know what to do, but you're stick of staring at your cheap, old TN displays, head to ebay and grab one of these
for about £230 (after import duty) to tie you over. It's PLS (so realistically you're going to see 5ms G2G response times) and it's all-but-guaranteed to reach 90Hz according to forums, though you might get lucky and find it'll do 144Hz. Sure, the stand isn't that good but if it bothers you just buy a VESA100 adjustable desk clamp which is way better than any footstand.
If and when Freesync comes out, you can decide whether you want to "downgrade" to a TN panel to get the Freesync goodness, and if you do you'll appreciate already owning a PLS panel so you can read websites, watch movies and do graphics work without suffering the disadvantages of TN colour reproduction and gamma shifts as much as 30% from the top to the bottom of the screen.
I had a 120Hz Samsung 1080p 27" TN screen a few years ago, and supplemented it with a 27" 1440p Korean IPS panel similar to the one I linked above. Within two months I'd sold my TN panel on ebay and bought a second Korean screen. No review can prepare you for the difference you see with your own eyes, but as long as you don't mind using ebay or similar, you can get these screens cheap and sell them on for very little loss if you don't like them. TN is nasty but fast. IPS/PLS are beautiful but slower. As someone who's colourblind, I didn't really think I cared about better colour reproduction but the difference was so huge that I really, really