For me, there were no pros.
You can make your members add more details when they sign up, if you want more details on each member. The problem is, it may make less people join your group if they have to fill in additional details. You will receive all group member's email addresses, although this will only help if you want to build up an email list. Bear in mind, unless they willingly gave their email address to you then they will likely cancel subscription as soon as you send them your first mass email. So, it's possibly a waste.
They give you some random stats about who joined etc., but unfortunately with all Meetup groups, just because they join it does not mean they will attend. So your stats will be so skewed so much that they likely won't be relevant.
The worst part about Meetup Pro is that if you try it out for the 30 days for no cost, you can't cancel it yourself. You have to email the Meetup people and tell them you want to cancel. However, they cancel your entire membership, not just PRO. Then you have to go back and begin your organizer subscription again.
Too painful to try to try it out until they fix all the bugs.
Cheers,
Mat Clarke.
