I own a e6600 and an e7200 and i can tell you that with my samples the e7200 is a far better overclocker
Pushing my e6600 to the limits i can get 3.6ghz fairly stable , whereas ive had my e7200 to 3.8ghz without pushing to the limit (both currently run at 3.2ghz).
The other massive improvement is the power consumption, the e7200 runs on a much lower vcore and generally means its cooler as well.