With SmarterMail 15 or earlier, I used the tool: SmarterMailLogAnalyzer; I will try to develop a similar tool to the one in the image you sent.

The most important part of email filtering is inspection by a human Subject Master Expert. That step is how we identify problems and create exceptions.   I have decided to call this the "SME filter."

Neither SmarterMail nor Declude provide adequate support for SME filtering.  Someone else can comment on rSpamd and Spam assassin.

Currently, I use a Barracuda appliance as my primary message review tool, but I am interested in alternatives.  Any suggestions?

Douglas, I am a "SME filter" of sorts. Using previously Declude and now DR. 

In my filtering (In case you are not aware, I have been using and involved in Declude since about 2001) I have it so that when certain things are triggered, the result is the email ends up in one of several manual review folders. I then manually review them using an old software (that really needs a new version) called FPReview. That allows me to quickly review the emails held and either return to queue for delivery processing or delete or move to a folder for further in-depth review.

I have to do this because the company I work for is in the hardest industry to do reliable practical and safe inbound email scanning for. A lot of this has to do with the fact that we deal with a lot of countries and email domains that most companies would just flat out block, but we can't.  

And yes, using this strategy (that I have developed over the now 23+ years) I am constantly adjusting filters and even creating new filters and adjusting processes.

I tried testing Declude Reboot, but I am stuck and have not gotten the help from MBF that I expected.

I am using an appliance that is only getting security patches.  It has some frustrating design inadequacies, but that lack is mostly offset by its pricing and the protection Declude provides by setting in front of it.   You have an equally dated solution.

This community really needs a message review tool along the lines of the one described at the beginning of this post.    I don't think ST has the resources to build it, because they have their hands full with email protocols.    

Much of the commercial filtering industry has gone to the cloud, has  a high price tag, and may not be able to cope with a Declude or Declude Reboot configuration sitting in front of their cloud service.    I don't know where to turn, so I keep making do with the Barracuda.

This would be nice!