that's why a Titan is not a "gaming" card .... cost too much and the same gen top dog of each brand are, either above or on par, like the 780Ti or the 290/290X also with the current gaming scenario of today, rare are the games that reach more than 4gb usage hence 2gb more means nothing. (bound to change once the 8gb and above will be a standard ... but not too confident that it will be a "instant" change )
again i paid 189$ for my 290 ... AMD reputation to be the underdog and the false argument of power consumption, as i am one to not care about... so that's personal
(associated with the cliché that you need a nuclear reactor in your backyard to power one card) make the price of the 290/290X sweet.(while you can still find 780 and 780Ti going for around 500$ where i am ... for no reason other than being nvidia... )
for the 980 and 970 ... if i where you i'd wait until the 980Ti and R9 3xxX wave calm down and the price are fully known.
also this^ (tho 60fps stable at ultra seems to be a must for the OP
)