[Koha] Sirsi to Koha data migration

Hello all, I would like to hear from any libraries or consortia that migrated to Koha from Sirsi. I am most interested in the ease of gaining access to bibliographic and user records for conversion into Koha. I know of one school district in Montana that had trouble accessing their records and had to pay for extraction from Sirsi. If your library has made this migration and would share your experience with me I would be grateful. Best Lee Phillips Butte Silver Bow Public Library Butte, MT