To make the best use of it, you have to understand your spammers. For example, they often use spam mails like 163.com, inbox.ru, bk.ru..., so you put those domains, or part of those domains in your spam list.
I tried several ways to bypass this anti-spam but failed. But even when some advanced spam bots can bypass this, it can still protect you from "average" auto-keying bots. For human spammers, you can create a unique question that only real users may answer.
The tool has some other features to protect you. If you understand your spammers, you will find the tool useful. For example, if your spammers speak Norwegian language like the ones that come to my site today. You put some common Norwegian words in the spam list. For some other languages, the tool already has the feature to stop those languages.