If you're on a 270, this card would be a major boost. If you're budget conscious, somebody's used 970 (there will be quite a few flooding the market soon as always when a new card comes out) would give you
double your current performance in some games. If you're feeling the burn for a better card, this could tide you over until big Pascal in 2 years time, or little Pascal next year if that's your style.
As to your general question, we have no idea when Pascal will hit or be announced. It will be 2016, but it could be Q2, or Q3, or Q4, it all depends on when the technology is ready and how fast AMD moves on their own range of cards.
Maybe, but there's no real risk in talking to them about it. They gave me a partial refund on my 970 twice, second for the mem fiasco, the first one was because I just asked if they would be retroactively honouring the Ubisoft game deal to people who purchased their cards before it was out. I told them in the E-mail that I wasn't technically eligable for it, but they still gave me some money back anyway. It's lunacy, but what the hell, not gonna complain.