I just discovered HappyFish and its wonderful, analogous to a TiVo for podcasts, but I have noticed a few rough edges that I wanted to bring to your attention.
One, which can certainly be considered a bug, is that when you sign up for a new feed and set it to keep the last N items, what I observed was that it downloads every item after signing up for the feed. Then upon the next check of feeds, it deletes all the older feeds past whatever number you set to keep.
Well, one of my feeds had 124 items, so HF basically downloaded 2 GB and then deleted most of it at the next check.
I suggest that it would be much better to use the limit at the first check. If the feed contains over N items, then HF should only download the last (newest) N items from the feed.
Thanks for the great program!