I had a used professional model from a juice bar until about 6 months ago when the motor burned out. The thing was a stainles steel monster at about 50lbs. I got it for helping a friend design all the ads and menus and stuff for his his health food store. IIRC it had a monstrous 4 HP motor. Most home models nowadays have a 1/4-3/4 HP motor. The stronger the motor the better usually, especially if you tos the whole item in there, rind/root and all, like I do.
Champion juicers are some of the best out there and same with Omega. I know many health food stores that use them. They make many smaller personal models too. I have been told though, by many people that the Juiceman 2 is pretty good and a good value. 4-5 people I knw have them and they juice almost every day with no problems. Only one person I know had their motor fail on them, but got it replaced via the 5 year warranty. I may get one myself soon. I just hope I don't grow those big eyebrows like the juiceman
Here is a comparative chart of some common home juicers.