Managed to over complicate what is in effect a simple process. The display is confusing at first, and takes some getting used to.
Multiple accounts, Tweetie handles multiple accounts much better. As for functionality Twiittelator Pro is still by far the most feature rich Twitter app for the iPhone.
On the plus side TweetDeck is free. But as I say, cluttered user interface really put me off. Remember this is a personal view, some people will love TweetDeck for iPhone, I am not one of those people.
Would be interesting to see a super light-weight twitter app, with just home screen, @ replies, and DM's. In a way they all overcomplicate it and m.twitter.com is the killer "simple" mobile app.
Haven't tried Twitterlator Pro yet, went with Tweetie and was happy enough with it to stick with it.
In either case, the more quality apps the better.
Hi Adam if it is a very simple lightweight Twitter app you are after I can recommend NatsuLion for the iPhone. It is a really simple Twitter app.