The high end ones usually have more functions... an example would be the clickstation. You can program in midi files, pre-set your "beats" and all that stuff. Don't get me wrong, its a great metronome, but its overpriced at $300, and TBQH, I didn't need all the functions.
IMO, it doensn't matter if you're just starting out or a professional drummer. As long as your metronome keeps accurate time, allows you to change the more important settings, and is reasonably priced, its a good metronome. Ie. the Boss DB-99 or something like that. It's like $100+ before discount, and its solid. Small, compact and gets the job done.