Being in the house selling/buying market right now, I'm very happy with my agent, who I've known for many years (he is a residential general contractor too). My observation is, however, most other agents suck. They either drag their clients around to far more houses than their clients could possibly be interested in (wasting the sellers time too), or they're flat-out incompetent. I think we're in the home stretch now (current house in escrow, new house in escrow), but we've had so many false starts due to agent/client f-ups (not our agent's fault) already, I'm totally conditioned to think of all the things that are still left to go wrong.
If you choose this as a career, whether part time or full time, please do your clients and all the folks on the other side of the deals a favor, and be competent at your job!