Significantly less spam
I had lots of blocks on my site, but the spammers got past them. Then I figured out that the blocks for specific files would negative general blocks.
I removed the file specific blocks I had for wp-comments, and lumped all my blocks in a general lump.
I’ve had significantly less comment spam since…
But frankly, I think much of the decline has to do with the spammer with the broken user agent I reported on a few days ago.