Haha max stable without going to extreme cooling methods. Thats a pretty good clock though, it just proves my point more that oced the sandy bridge out does the ivy since ivy isnt as overclock friendly. Ive seen countless ivy bridge cpus top out at 4.8ghz.
To the op: Watch the video on youtube, this guy explains very well the differences between the two in terms of performance. Core per core with the same level clock speed (including same level of oced clock speed) The ivy bridge always comes out on top by 10%. However when it comes to ocing to max potential thats when the ivy bridge gives out, and sandy keeps going. So it depends what you wanna do in the end.
Verdict: For slight oc go ivy bridge 3770k
For Heavy overclockers 2700k http://www.youtube.com/watch?v=c6zUE-dlPfs