4870 crossfire vs. 280gtx

Everywhere I read people are claiming 2x 4870 in crossfire beat a single 280gtx. However, the review charts in this website have the 280gtx beating the 4870s by quite a bit almost every single time. Also the 280gtx is quite a deal less expensive than 2 4870 cards. So why is it everywhere you turn people are bashing the 280gtx? This is the only part of the current upper end cards I do not understand.

9800GTX+<4850<260gtx 216 core<>4870<280gtx<4870x2

Where do the 4870 and 4850 crossfire fit?

Thanks, that's helpful. If those charts are totally accurate, then that means that 4870x2 in crossfire actually REDUCES performance over a single 4870x2.. odd. Also looks like the 280gtx is beating the 4870x2 in several games, but I thought the 4870x2 was always top card.. and in fact I've seen benchmarks where the 4870x2 beats even 280gtx SLI none the less just one card..

The reason quad 4870x2 performs badly in some games is because it's still new. While new drivers don't increase single gpu performance by much, dual will get some gains, and quad a lot of gains. Eventually, quad 4870x2 should scale just as well as quad 9800gx2.