I had several issues importing my members from membership 1 to membership 2 but we did finally seem to get them all. However since I've noticed several problems popping up.
1) The membership (there is only one.) should never expire and run until the user cancels it. Imported members have expiration dates and some have expired which I have had to manually fix.
2) Despite resending the payment data from paypal as requested in this forum some members payment dates didn't transfer which I've had to just try and notice to date.
3) User history on most of the imported members has all of their past payments accounted for on one date... not really much of a history and a bit confusing for them.
#1 is my most concerning issue but help on 2 and 3 would be nice too. I'm granting access through the dashboard now.