Don't let these flaws stop you, though--Persona is very well done and constantly getting better. I've had hundreds of people sign up for paid accounts and only two have had trouble to the point of asking for help. (And nobody's cancelled their subscription because of login problems. :-) )
Just as a point of info "only two have had trouble to the point of asking for help" is a really bad way of judging whether something is working well or not for your customers.
The vast majority of people do not complain if they hit problems. They just silently go away. From my experiences of optimising this sort of stuff I'd pretty much guarantee that you have at least 10x times than number failing and walking. Possibly much higher.
Not in this case. The signup flow for my site is "decide to subscribe, put in email address, put in credit card, create Persona account."
By the time they get to the "create Persona account" part, they're already invested in it working.
I also monitor my logs for signs of trouble. One of the two issues I was talking about above was actually initiated by me reaching out to the subscriber. (I happened to see them bouncing on the "now log in" page within a few minutes of their subscribing.)
And I also ask people who cancel why they did so. The vast majority respond, and none have said "I couldn't log in." :-)
It's quite possible there are still some angry silent unsubscribers who were stymied by Persona, but at this point I'm satisfied that it's not a significant number.
Just as a point of info "only two have had trouble to the point of asking for help" is a really bad way of judging whether something is working well or not for your customers.
The vast majority of people do not complain if they hit problems. They just silently go away. From my experiences of optimising this sort of stuff I'd pretty much guarantee that you have at least 10x times than number failing and walking. Possibly much higher.