Have seen a recent increase in spam – any insights as to which spam blocker is working best out there?

@sharijstauch I’m with @wade-harman – I use GASP (http://wordpress.org/extend/plugins/growmap-anti-spambot-plugin/) to deter software generated spam and Akismet to get the rest. Some still slips through though, and you have to take a peek at your spam filter with Akismet regularly to save some legit comments that get lost in the shuffle. But the combination cut my spam from 100′s a day to maybe 15 or less which is a good thing.

Actually, you will have to purchase the CommentLuv premium plugin to get this I believe.  And, since its 2013, Andy is doing recurring payments on this plugin. You can check it out here to see what changes are being made with this plugin.