If I were looking I would want to be able to do a demo. Not watch them do a demo but be able to play with it on my own a bit. I would be asking about electronic capabilities such as can I submit thru any clearinghouse I choose, or am I limited to the clearinghouse they push (most push a specific clearinghouse and I rarely use the one they suggest for cost reasons). I would want to see the report capabilities.
Those are the first things I check. Make sure the system is easy to navigate, and that it can do what I need. Then I consider cost vs what I'm looking for. I do not go for the cheapest, but I consider what I'm going to pay vs what I'm getting.
Hope that helps.