In general quite well. It is a B2B product and being able to pay gives them some assurance that there will be someone behind. The freeware version continued to exist, and the transition to actually pay was long (free beta for the subscription lasted 4 months). We also did a heavily discounted launch promotion so that the transition from nothing to something was a lot smoother for existing users. Here is the announcement we did: http://www.apsic.com/blog/?p=25