Tapatalk for iPhone:
Showing New and Unread Posts:

Full Thread Viewing and Pagination Support:

See Who's Online:

Reply to Post and Image Upload:

Some of the large forums activated Tapatalk support

Tapatalk for Android
Total Android Look and Feel

Same feature set as iPhone:

Quickly Reply to a conversation:

Latest and Unread Posts indicator and multi-tabs support:

Full screen image support - support landscape mode also

Check out http://www.tapatalk.com for more information!