Must be some monster hedge! We cut hedge post all the time with our 361 Stihl. I've got a JD CS 56 just a little 4 hp saw, it was made by efco, it's been one heck of a saw, no issues at all, it's better built imo than the home owner stihls and huskies, pro-construction, etc. If I were going to use one for hedge cutting I'd go to local dealer's and find one I like, and buy there, hedge is tough, especially seasoned, it can be hard on a saw, I'd rather have a dealer with good service any day, unless you can save substantially by going mail order or internet. Lot's of good options I prefer Stihl because I have had over thirty years of outstanding performance and reliability, 441,460,650 or 660 should do anything you want to, Husky 372's are supposed to be bullet proof and people here rave about the 7900 dolmars.
Get ya one and make some of those pretty yellow chips.