DO NOT BUY THIS PRODUCT (read on if you care about the accessibility of your sites and if you value your time...)
There are serious flaws in WP IPBlocker Pro that will cause it to block your own IP address which will lock you out of your own admin. EVEN IF YOU HAVE EXCLUDED YOUR OWN IP as instructed. Also, blocking configurations other than explicit IP addresses can simply stop working. For almost anyone, the free version that blocks a list of explicit IP addresses is probably adequate PLUS you will not be taking any risk that your site becomes inaccessible to you (unless you really are careless enough to put your own IP address on the list).
The country blocking, timed blocking and explicit access features in the Pro version would be great if they were reliable, but they simply are not. Other than being blocked from your own site, if the blocking of countries or IP ranges fails you simply will never know. The real issue in all this is that only corrective measure is to provide LionScripts tech support with FTP and database access so that they can clean out configuration settings and data. While it's nice that LS provides this tech support freely, who has the time for this nonsense? If you can afford to have your site(s) go offline and have the time to waste bringing them back, then maybe the risk is worth if for you. But be warned that if you purchase the Pro version and determine it is too risky for you to use or does not live up to its claims, YOU WILL NOT BE ABLE TO GET A REFUND. The developer has done nothing to protect the underlying code (which is simply an extension of the free version readily available in online repositories - which you could extend yourself if you wanted to) and so will claim that they cannot invalidate the software and so you would most likely use it for free after a refund. So LS will not only blame you for anything that does not work properly they will ALSO imply that you are likely a dishonest customer who is simply trying to get something for free. LS will send your their "no refund" policy in support of their position ... a policy that is NOWHERE to be found on their site or landing pages where you are likely to purchase the product.
There is ample evidence in online forums that these problems exist and that they occur often enough to warrant concern about using this product on any site of value (and if your site does not mean that much to you, then you probably don't care to go this level of protection anyway).
Bottom-line - JUST DON'T BUY THE PRO VERSION or you will likely regret it at some point.