Not long ago, tomshardware did a shootout of boards and the benchmarks revealed less than 2 percent variance among the boards. That was within measurement and human error so the consensus is that given a board with the same chipset there is likely to be no performance change from one to the other.
So that's out of the way.
You may want to compare which has the better price or if there is some layout issue, ports or slots that you prefer but you didn't reveal that. Maybe it's just the price?
At 1K I'd rather build this one -> http://www.pcworld.com/article/2040319/build-the-ultimate-intel-haswell-pc-for-under-1000.html
I am planning to build a gaming rig that is around $1000 to $1500 which motherboard should i choose i am planning to use an i5 the boards are: Z77A-G45 motherboard and the ASUS P8Z77-V LK. thanks for the help:)