If you NEED a new card now and are willing/able to pay current prices, then go ahead and upgrade. If you WANT a new card, then only you can decide if your willing to pay current prices or wait and gamble on speculation. If you don't need a new card and are okay with current performance, then wait. No more complicated than that.
Until the next gen product is released EVERYTHING is speculation (performance, price of old gen, availability, etc.). There's also always something new on the horizon...