It has better fonts and whitespace than bazqux (to name one I like), and it's better for reading a lot old comics. Most feed readers seem to be designed for reading today's new postings quickly rather than binge-reading old xkcd.
Glad you liked it! Here are some of the popular ones we've done: http://blog.filr.io/we-heart-webcomics/ If we've missed any of your favorites, let us know and we'll get it done.