Ok so I’ve been using Tweetie 2 for just over 24 hours now and here’s my initial thoughts compared to Twittelator Pro.
Tab bar

- While Tweetie 2 now informs you that new tweets have arrived since the last time you launched, it doesn’t show you how many.

- Whereas Twittelator Pro actually shows you the number of tweets which have arrived since the last time you launched it.
Tweet confirmation
Twittelator Pro displays a pop-up notification letting you know that your tweet has been sent. Tweetie 2 doesn’t give you any confirmation that the tweet has been sent and this is a problem when tweeting photos or large videos.
Attached photos
I also prefer the way Twittelator Pro displays attached photos:

- Tweetie 2 indicates attached photos with this icon.

- Twittelator Pro shows an in-line preview of any attached photos.
- Tweetie 2 has no ability to ‘hide’ users.
- Tweetie 2 now supports TextExpander when composing tweets which is great, however I’ve noticed if you use this feature it results in a 4 second hang or lag each time you press ‘reply’ or ‘new tweet’.
Without a doubt both are great Twitter clients, for UI Tweetie 2 wins hands down (the way you refresh tweets is just pure class) but if you’re looking for a feature rich client Twittelator is the winner IMHO.