4 5750's in X-fire: gaming performance?

jaguarskx posted a wonderful thread full of reviews of this card, but while most of them went and did single card and 2 way Xfire reviews, I was wondering about 4x5750s.

I need to run two monitors for certain stats programs I run, and two more connections will be provided to TV's in my house. Another will be for just gaming in my home office. I was thinking two 5870's, but thats nearly $700. Four 5750's can be had at $500.

I game at 1650x1050. Anyone know what 4way xfire is like with 5750's? Predictably better than one 5870 I would presume, but in comparison to say, two 5850s, what are we thinking?