When it comes to a twitter client for either OSX or iOS what are your favorite features in an existing app and/or a feature you wish existed?

I like simple looking app, white space is awesome

I still use old version of TweetDeck before Twitter bought them just because I can't get it in anywhere else. Features:

1. Click "reply" from multiple tweets and their names get pulled into the tweet I'm typing.

2. Multiple streams I can arrange accordingly.

3. Multiple accounts (including non-twitter accounts is cool).

4. Shortening services that let you use your API key (ex: bitly).

5. Global filters (sources + containing words)

6. Ability to sync the settings from one client to the next.

7. The TweetDeck feature "Retweet button should" to change from old style or new style RTs.

8. I like how Twitter.com combines RTs/favorites of your tweets into one "post".

9. Common actions right in the app like blocking, favoriting, etc.

I'm pretty happy with the native apps (Mac and iOS), except for the lack of Retina support on the desktop client. I'm sure they'll add it sometime though.

Some of the features that would be nice to have:
- One-click sharing to Instapaper/Pocket
- Buffer-integration (queue tweets)
- Basic stats about follower count and engagement (e.g. CTR of shared links)
- More prominent saved searches (vs. current implementation in native Mac client) with badge count of new tweets

I guess the real question however is which market is underserved right now with regards to Twitter clients.

Oosfora is what I'm using now for Mac since twitter cut out their support (or are rumored to). Tweetbot for iOS / twitter for iPad. I look for clean, simple & full featured. Has to have read it later, following/blocking capabilities, list access, etc.

I'm using Tweetbot right now for iOS and just the native mac app. I love using Tweetbot because of how it incorporates the other services I use, like Pocket and Droplr, as well as the gestures the app incorporates, such as the the slide left and right to view the conversation.

Honestly I haven't opened the twitter web app or iOS app in a long time. I'm not a big fan of the discover section, I really would just have better use of my tweets like Tweetbot.

My ideal client would be Tweetbot, but as the default client, that way it incorporates with the system better.

OH. And tweet syncing. I always want to be where I left off. Don't make me find my last tweet I read!

Inline notifications would be nice (new followers, added to list etc.).

CloudApp shortened URLs.

Add to Readability.

Mute hashtags.

Temporary user mute would be cool (timer?)