We have done several conversions to Genetec over the years and the process is just as Derek described above. Our first conversion was done with the predecessor to the CloudLink (Synergis Master Controller) and that college was so pleased they participated in a case study.
If you want to streamline the migration, but don't want to pay professional services, consider adding the license for the Import Tool, which will allow you to import cardholders in one large (or several smaller) batches. Sure, that doesn't handle all of the rules programming, but I would rather have my technicians program the system than to migrate suspect data from a legacy system. The cardholder setup is the most tedious part, in my opinion, so this $1,000 (MSRP) utility is well worth the expense.