I purchased their premium plugin to gain complete functionality. I know there are some free plugins that have some of the features of the premium plugin, but compare those support threads to this plugin. I found other plugins to have many problems whereas this one has been smooth sailing. Needless to say I applied common sense to my purchasing decision – would I rather save a buck and get a free plugin that will likely have problems/false positives or upgrade this to the premium version. It was a no brainer for me because one unwanted lost sale would more than pay for the cost of this plugin. Anyway, I don’t want to deal with the problems some of those people are dealing with when it comes to the free plugins.
I’ve been on the premium version of this plugin for a month and love it. There’s no impact on site speed and it’s been 100% effective at blocking orders from the time wasting/scamming customers that cost us money. It’s money well spent for anyone serious about their business.