I have the EPoX board you're talking about, and it works great for me so far. If you're talking strictly performance, then the DFI board is best, but the question you should be asking is, "Which motherboard best suits my needs?" Both boards are great overclockers, but the DFI is given the edge because it has more options to tweak, and thus gives you better performance out of your system. If you're just starting out with overclocking, then the EPoX will do you just fine. And at approximately $20-25 cheaper than the DFI, I think it's a good deal. If you have absolutely no intentions of overclocking, you might be better off saving even more money and going with a different brand all together, such as MSI.
Here's some reviews for you to look at:
nForce 4 Motherboard Roundup