Federico Viticci wrote an epic piece for MacStories examining iOS Twitter apps:
For the past six months, I’ve been reevaluating my entire Twitter experience based on the apps I use to read tweets and interact with people. The idea made a lot more sense once I stepped out of my preconceptions: I wanted to understand what 2014 Twitter was like and if that meant sacrificing my nerd cred and use a Muggle’s Twitter app, so be it. But at the same time, I’ve gone back and forth between Twitter and third-party clients, primarily out of habit, but also because they still offer powerful features and design details that I appreciate.
I've been using the official Twitter client on my iPhone and iPad over the last couple weeks, and I'm generally satisfied with it. While there are things about Tweetbot which I miss, Twitter for iPhone really is a good app. Whether I stick with it long-term remains to be seen, but for the time being, I'm not missing Tweetbot that much.
See also: "Hacking the Tweet Storm", by MG Siegler.