I agree that getting an appraisal up front is a very good idea; however, the appraiser will make a big difference too. Get the best local appraiser you can find that does a lot of appraisals in the area. Don't just pick any appraiser.
I'm always amazed at the questions that sellers looking to list do not ask the agents, such as the following:1. How long have you been selling real estate?2. Is real estate your main occupation, i.e. do you sell full time?3. How much have you sold the last 2 years.4. Where will you be advertising my home?5. What MLS systems will it be included in? 6. Can you provide me a Comparative Market Analysis? These are basic questions that most sellers never ask the agents; therefore, they end up with new agents that have never sold a home, and are wondering why their home has not sold.