not bad but not great. i'm running 4.2ghz @ 1.288 and I don't have as good as a chip as a lot of others in this thread. i'm sure you'll hit 4.2-4.4, just with a lot of extra voltage.
and as for the qx vs q, i would def agree the Q's are a much better choice, even if you did only pay $200 for the Qx. the Q's have a much better track record for awesome oc's.