We actually got lucky, we acquired a business earlier in the year. Response from the people transferred over was that their IT company was actually well liked, knowledgeable, and good at communicating issues. As we required their knowledge of the systems we transferred over to us, we also transferred their support as well. As a result we were able to work with them for several months. Not often you get to "try before you buy" in this business. It certainly made the decision to switch a lot easier.