Haswell vs Ivy Bridge

[refllect]

Is there a big difference in benchmarks?

 

[Onus]

No, not really.
If you're not interested in overclocking (or only very mildly), get Haswell; it does have slightly better performance at stock.
If you ARE interested in overclocking, get Ivy Bridge. It overclocks better than Haswell (less heat, anyway), so you can typically match the performance.