Decided to give Evolution a chance as my main mail reader. Wrote a little script to make the subfolders, since the UI for this is not so great. Also made filter rules for all of the folders I have in Gnus. It is so far much easier to do in Gnus.
Pushed 180 MB of email through Evolution's filters. It still has some scaling issues. Apparently it indexes the spool before importing it (which it does in memory). I had to make an emergency swap file so that I didn't run out of swap.
Also, importing new mail is pretty slow too, since it seems to be re-indexing all of my folders again.
Dinner at Fire 'n Ice with Bambino, Federico, Joe, and Miguel.