depends on your goals. AMD 290X gets the most hashrate, but it draws a lot of power.
the nvidia maxwell architecture is much more efficient.
Thanks, are there some "hash table"?
for the AMD cards you can take a look at the claymore GPU miner thread. It has most cards listed with diffrent memory types (elipa/hynix). There might also be a change in favor for AMD with the new line of cards that should be able to match nvidas maxwell architecture in terms of energy efficiency. But I guess we will have to wait and see until someone buys a Fury card and mines some XMR.