MSI has OC'ing in windows too, BUT I don't ever recommend OC'ing within windows if you can do it in the BIOS. It's a much more reliable and stable way of OC'ing so I don't consider that as weight going towards one board over the other.
Also Trifid typod here:
that one on ebay is socket 939, and it would not be compatible with that board.
The one on ebay is socket 754 not 939, and you want 939, so dont bother with the ebay one.
Regarding '3rd eye' he's referring to a specific board. The ABit AV8-3rd eye, it comes with all software you need for temp monitoring and/or OC'ing but so does MSI. They have something called Corecenter that does the same stuff, only no quite as in depth.
BUT like I said I suggest if you want to overclock you become familiar with the basics, and also familiar with the BIOS layout and OC through the BIOS not windows.