The first link is broken, brings you to newegg page with following error:
"You must first designate which items to compare by clicking on the appropriate check box in the product listing."
So you want to know which you should go with: GA-Z68XP-UD3 or Maximus IV?
Pros for the GA-Z68XP-UD3:
1.) More stuff: Firewire, +2 PCIe x1, +2 PCI, +2 SATA III (6Gb/s)
2.) $30 cheaper.
Pros for the Asus Maximus IV:
1.) ROG connect (Gigabyte board doesn't have)
2.) 2200MHz memory (Gigabyte - 2133MHz, Asus - 2200MHz) Not really much of a pro
3.) Better overclocking performance (not sure of this, but I ran into a few things that led me to believe the board is good for overclocking)
Basically I would go with the GA-Z68XP-UD3, unless you really want ROG connect. If you want a higher overclock then you might want to look into which board would be better for that, but since you didn't give any indication of what your priorities are then I would go with the Gigabyte board.