I think this was a big factor in why AIM trumped ICQ in America. ICQ had that "sending mail" icon that took a few seconds (or more) to "send" your message and it didn't quite feel instant.
The earliest version I remember, before 98a, had a history button that would show the running log on the top of the message box window, which was nice.
The nicest thing about ICQ for me back then was the fact that the message disappeared when you sent it -- it wasn't there filling your taskbar or occupying your mindspace.