The truth is that Skype totally dropped the ball on iPhone and AIM client was so bad, it was most of the time unusable.
The new application, Nimbuzz, provides support for most of the chat networks in the nice package.
Big pros for me:
- All networks in one design - no switching
- Skype - finally a good client
- AIM / MobileMe / iChat
- big horizontal keyboard typing
- no photo transfer (yet)
- the list of contacts is very long, it would be nice if they were sorted by status ("online" on the top)
- (option) hide all "Away" contacts
- AIM often shows message that it is "temporarily unavailable"
- no full names of the contacts (frankly I don't remember all the user names of all the people I have)
- ability to make fonts smaller in the chat to show more messages while typing
- better fitting of the messages (balloons?)
- no group support (yet), I need a small groups like "friends", "work" and "all others"