I am a buyers agent and I think the most important things in this market are
1)Do you do Real Estate full time? If they are part time it is difficult for them to take you out touring and return phone calls in a timely manner, unless they are doing RE while working at their day job.
2) Will you be helping me through the entire process of buying a home? It's not just about finding a home for a buyer. They should be able to help you through the mortgage process, be there for inspections, make sure all paperwork is to the lawyers or whomever they need to be. Make sure you have set up your utilities, etc.
3) Once your in your home will they follow up and make sure you don't have any questions. This is especially important if you are not from the area. Doctors, Lawyers, schools, mechanics, camps, etc. We have alot of that info and if we don't we have the resources to get you some recommendations. I have even recommended a few financial advisors. Good luck in your search for an agent.