congo on you're purchase, happy gaming, but some wrong perceptions over there, since you dont know any dates when maxwell and pirated islands will hit india, and since the current techs are just doing good with healthy competition, its too unwise to predict and wait for the future tech to come rescue in VFM war. You want more perf/buck in future , of course there will be, but you can say the same thing then as well, "i will wait for XXXwell or XXXislands coz they will be future proof, more power etc etc" and so on and so forth...so what MAY happen in future and what IS now, is no where there to compare.
Mantle is not implemented now, even you can write you're own mantle, its not that significant, then getting a card with 2.4K extra with same (less actually, lesser in OC) performance with the other ??...
11.1 will do well enough is games right now, no company is stupid enough to skip such support in future just to ruin business in a upgrade platform. if you bought 760, its a very good deal indeed.