After having installed wp-spamfree now for a few weeks I can say with absolute confidence that this is my comment spam filter of choice now.
As noted previously I used the automated install procedure for it and then activated it. Since then not a single bit of comment spam has required my intervention.
Highly Recommend 10/10
The major problem with wp-spamfree is that you are bound to lose a lot of valid comments if you use it. Many common words are apparently blacklisted in it so anyone who happens to use one of those words will get a message that their “comment seems spammy”.
If we could back up and edit it that might not be so bad but usually when we backup the comment form is empty. I don’t know about other commentators but when that happens I would have to be extraordinarily motivated to bother to try again.
Just so you know I didn’t trust wp-spamfree initially and turned on the full logging facility. I then read through every single spam looking for real comments that had been caught and not a single one had. The great thing about opensource software is that you can can view the source code and modify it. If I had found one or two valid comments had been blocked I would have edited the source to remove the cause of these failures.
I am however very happy with wp-spamfree as it saves me having to wade through 100’s of comment spams a day in the akismet queue. I take what you mean regarding backing up and the form being blank I would also give up at that point.
I stand by my recommendation of this software however as it is extremely effective.