1)Stitcher inserts it's own ads into podcasts
2)By doing #1 they often re-encode the original podcast at inferior rates

3)Overcast has a feature that allows you to listen at a faster rate WITHOUT speeding up with the pitch or making it sound like the disclaimers used at the end of commercials.

The only "bad" sting about Overcast is that you have to download the episode before you can play it - so no streaming downloads.

plus I like the user interface on Overcast - they buttons are BIG - and I listen to podcast while I hike and it makes it easier to use while I'm walking.

I had been using Downcast and Instacast before Overcast came out.