What I've seen so far of the new Twitter has impressed me. I never used Tweetie, being relatively new to the iPhone scene, but I have had some experience of TweetDeck on both the PC and the iPhone, and I have to say I prefer this. Never a great fan of the rather confusing TweetDeck user interface, I find the Twitter interface refreshingly simple and easy to use. Unlike TweetDeck, you don't have to spend ages adding columns to display the tweets you want to see; instead everything is just displayed in a single stream (which of course is true of the default TweetDeck setup as well, but somehow seems less confusing). However, you also have instant access to any of your Twitter lists (again, in TweetDeck you have to set these up for yourself) so it's very easy to filter out the tweets you don't want to see at any time. Because this is the official Twitter client, any customisation you've made to your account on the web - lists for instance - are immediately available in the iPhone client. No additional work required on your part.
Twitter has some great, even killer, features. You can install a bookmarklet for Safari so that you can quickly tweet any web page you're viewing. Strictly speaking I suppose this isn't part of the app itself, but it's a welcome addition. Twitter also has support for offline readers such as InstaPaper and Read It Later. This is a brilliant addition: with just a click you can add an interesting link in a tweet to your reading list for later offline perusal.
Another neat trick: swipe across any tweet in the timeline to display an online toolbar giving you access to common functions such as favouriting, retweeting, or the aforementioned offline browser links.
Twitter is pretty nippy as well. I hate to make the comparison again, but it's the only one I have: it's faster than TweetDeck, which always frustrates me with amount of time it takes to update.
Unlike TweetDeck, Twitter doesn't offer support for Facebook information, and you may see this as either a failing or a virtue, depending on your taste. Personally, I lean toward the latter opinion; Facebook has its own perfectly usable iPhone client. The only feature that you do lose is the ability to update both Twitter and your Facebook status with one tweet. A shame, but I can live with that.
In conclusion, then, I would definitely recommend the new Twitter client to any Twitter user with an iPhone. In fact, even those without Twitter accounts can use the app for searching and browsing, and of course there's a convenient sign-up form in the app for those who decide to take the plunge. I believe it makes Twitter less confusing to use than TweetDeck, it looks nice, and it's a joy to use. And you can't argue with the price.
