The MSI Twin Frozr and ASUS seem to be the two best 7850.
As far as the overclock goes, you could easily put it to the CC max core of 1050. That should run fine at stock voltage without producing much extra heat. Many people run their 7850 at 1100 to 1250.
While no overclock can be guaranteed (unless it comes with the overclock), 1050 or even 1100 seems to be guaranteed* on the 7850 cards. And with how well the Twin Frozr cooler works, there shouldn't be a lot of extra noise either.
*Disclaimer: this post in no way, shape, or form guarantees that you'll get a 1050 or higher overclock on your 7850.