As it has been stated by the other realtor's there is no list to compare each realtor to another. What I would suggest is for you to get a list of question's together and interview a few realtor's. Pick the one you feel gives you good information on your property, what they are going to do for you to sell your home and the one you feel must comfortable with. Make sure you are a good fit for each other. If you have any question's feel free to contact me any time at: http://www.cathyhornung.com
The multiple listing service (MLS) is where buyers agents search for properties to show because with their dues they receive "real time" listing information -not screen scrapings of the MLS that leave time period gaps in the listing information. They do this because there is no point setting up showings for homes with contracts pending and they have the most current data to identify this using a real time database.
As I have stated in earlier comments, with gas now being over $4.00 per gallon buyers agents are likely to be more pickey where they spend their time/money showing properties as most don't receive any compensation for showing properties - only closes with qualified buyers.
In a buyers market it is important that your parents price correctly for the area & condition of their property. You may wish to obtain several CMA's from different agents that help your parents assess the likely sales price for "as is" vs. making "cost effective" improvments. Some homeowners make the mistake of listing with the agent who provides the higest priced CMA. Listing agents are NOT buying your house.
I believe in hiring a seperate stager or an appraiser to help with valuation as they have no conflict of interest between telling you what you need to know vs. patronizing you to obtain the listing. You get what you pay for in life - have you ever really found it to be different?
Please let me know if you would like some referrals.