If you appreciate fine tools, the pro saws are the way to go. As others have said, pick the dealer you think will give you the best service, then choose the saw. Around here, the Stihl and Husky dealers are excellent; Dolmar makes a good saw but lacks consistent dealer support. On the Husky side, the 346xp leads the 50cc class IMO based on dependability, light weight, power, and handling. The newer 550xp is more of a crap shoot in terms of reliability; if you have a dealer who has embraced the new technology and knows how to fix them, then fine, but I'd still opt for the 346xp. On the Stihl side, the 50cc MS261 makes good power and is bulletproof, although it weighs more than the 346xp.
Personally, limbing is time-consuming, tiring, and a general PITA and I would not use a 60cc saw for this task due to weight and a longer bar than is necessary. When I started cutting wood bigger than a 50cc saw can handle efficiently, I jumped to the 70cc class for a 2-saw plan.