Both key points.
I started taking subscriptions a year ago today and have been very eager for 7.3 so I can integrate with PayPal. I was so hoping to be up and running with 7.3 by now.
Up until now, it has been a manual process for me. ID'ing each person who has paid and putting him into a subscriber group. That hasn't been too bad.
The bigger issue is renewals and failed payments. I have a lot of questions on how things will work when I finally move to 7.3.
For example, I'm having some subscription payments fail. For now, I'm not cutting off their access (i.e., removing them from the subscriber group). But once I upgrade to 7.3, how will I deal with these people who have fallen through the cracks?