I have upgraded to Pro on all my tough sites (one-time fee per sites owner) and we'll see how free holds on some others. The SUPPORT is fabulous and the extra help and WordPress tips are invaluable -- can't find anywhere else.
There is a learning curve, but most is wizard now, and support is very fast. Instructional Videos are great. Their forum is immense and they cull and prune for relevancy daily. I'm a VERY HAPPY customer who has benefited a great deal especially during these months of brute force attacks and login hammering.
Weird usernames, minimum 14 character passwords and Bullet Proof Security has saved my top blogs.
Thank you to their team.