Another important distinction is the use of cache - TwitterFon loads nearly instantly, displaying everything you've received so far, and downloads updates very quickly. Tweetie stores nothing - even if you don't have any new messages, you have to wait for it to re-download every old message, before you can tell! It's utterly maddening, and something that's been posted to their request forum for awhile, I suspect. All that said, I still use Tweetie - despite it's (major) short comings, it offered multiple account support when I needed it (long before TwitterFon added the Pro version), I like the setup (GPS to location or link, etc.), and I really do like the design. Not the iChat-style balloons, of course, but the smooth gray interface is a pleasure to use, IMHO. Given the shortcomings, however, I'll be keeping an eye on TwitterFon - any significant sale, and I plan on purchasing it. Just can't justify "full price" after already spending money on Tweetie! I know that makes me cheap, but I'm ok with that.