As it uses the stock cooler, it's likely to get very hot (unlike, say, the Gainward Golden Sample-version). Otherwise, the 4870 1GB would be my current choice too, even if nVidia made a huge online fuss about their new driver that gets the GTX 260 (216 shaders) faster than the 4870 again (in some games). All in all, from what I've read, these two cards are about the same level of performance and price and would both get my recommendation, and if you plan on going crossfire, the case is obvious: Go for it
[edit]
Oh, my comment about stock cooling referred to your link, which doesn't show an ASUS card, but one from Sapphire.