The freely available Notes Migrator for SharePoint Discovery Edition has been an amazingly popular product. I can honestly say it is now the analysis tool of choice for over half of the consultants and system integrators that I know of who are doing pre-migration analysis projects. I like to think that is not only due to the attractive cost, but also because it really nails the problem and quickly becomes a platform for consultants to perform their value-added work (including the inevitable manual analysis steps as well as the actual migrations).
I often get asked how someone would upgrade from the free Discovery Edition to our Standard Edition or Premier Edition. The answer is a good one: There is no need to reinstall anything on the client side --- just upgrade the license. All the data you collected and organized during the analysis phase now becomes the "home base" for doing migrations. If some cases, it is a simple matter of right clicking and migrating. Of course we give you a lot of help with the complicated cases as well.
The thing to remember here is that our Discovery Edition is really the entire product; most migration features are actually available in restricted trial mode (10 records per database). Certain Premier Edition features are disabled completely until you plug in the right license. Of course you may have to install our Import Service on your SharePoint servers if you have not already done that.