We did a fairly complex migration from two current shopping carts (OpenCart for a US site and Volusion for a Canadain site) into one new Magento website. The first full migrations happened with no problems. However, when the new site was ready to launch the «recent migrations» (to update new orders and customers) gave us several data problems. The Cart2Cart support team jumped in and helped get the «recent migrations» working properly and imported all of our data. I definitely recommend the Cart2Cart service and their support team is outstanding!
Scott Quarterman