Migrate User Account

I am moving users from one domain to another. I am using SPFarm.MigrateUser.

Why, oh, why did Microsoft make the SPSite.MigrateUser internal?? All the farm level migrate user does is loop through all site collections updating users at a site level, so why not allow the developer the flexibility to manage this themselves.

I have a situation where some users need to get migrated to newdomain\username and other users to a claims-based user id of i:0#.w|newdomain\username.

Using the farm level migration, the migration of users needs to be managed very carefully now otherwise windows authenticated and claims authentication user ids can get mixed up!!!