I picked up a msi mpower z77 for $100 brand new off eBay. It's equal to the Asus ROG series in terms of OC ability, components and features. Deals can be found, its just a matter of timing.
While the 4590 is newer tech, barely, its also a locked cpu. Just the fact alone that the 3750k is unlocked would be a selling point for me. Ivy Bridge can be delidded, dropping temps upto @10°C across the cores, runs cooler in general vrs Haswell cpus and takes a better OC.