I own both a MSI Z77A-G45 and an ASUS P8Z77-V LK. Which is better for overclocking? I'm using the asus with the 3570k atm and the MSI with an i3-2100. I'd like to overclock the i5 to something like 4.4/4.5ghz as i've got a xigmatek dark knight installed on it, and really don't know how to do so with either.
Both are great motherboards and you should be able to reach that if you have an OK chip. I doubt there is any overclockability difference between those two boards. Pick whichever suits you best / looks better aesthetically.
Why not test both? Then you'll know for sure which board is better for overclocking.
and really don't know how to do so with either
It's usually as simple as changing the CPU multiplier and tweaking the voltage. There may be other settings that you can tweak to help stabilize your system. Look for guides online.