IMO vs Wickr

Although IMO has a comparable, and in some cases superior, feature set when compared to the competition its key selling point is its interface.

From LifeHacker when it won "Best IM Client":

Signing on, navigating chats by tapping the tabs at the bottom, searching for buddies, and virtually any other operation is easy to find and use. The app, itself, is very quick. Even sending a voice IM, if you don't feel like typing, is responsive and sends quickly. Everything imo does it does well, but it's excellent navigation really makes it top notch.

IMO also has a fully functional website that you can use for chat while on your desktop or laptop. This really puts IMO ahead of the competition as you can use the same system on all your devices so you don't have to deal with overlapping notifications etc. (Note: IM+ also has this feature)

It should also be noted that it has the highest rating in the App Store due to both the UI and its stability.

Tabbed chats make it easy to switch between conversations

Both your buddy lists and chat histories are searchable.

Concurrent sessions allow you to be logged in on your desktop while also being logged in on your phone.

Unlike most, you can use your phone but you don't have to. You can register without giving anything and add contacts either via e-mail (only) or phone number.

Wickr has a feature that not only erases all messages, but also overwrites them with junk data.

Instead of using usernames, emails or phone numbers to find other users, Wickr uses hashes derived from phone numbers or email addresses (this applies to the find friends functionality only). Hashes are the result of a one-way cryptographic function, meaning it's purposefully difficult to reconstruct original data (phone numbers and email addresses in this case) from them. For Wickr, hashes are generated on the client's side so that no personal information is ever sent to the Wickr servers. The app finds people on your contact list that also use Wickr by comparing the hashes that get generated from contacts and comparing them to the hashes that are stored on Wickr servers.

Messages can have a lifespan between 3 seconds and 6 days. Received messages arrive locked. Once they are opened by the recipient, a timer starts counting down until the message is deleted. Of course, the recipient can still copy them or take a screenshot.

Wickr disables the screenshot functionality altogether when the app is open. However, there are ways to circumvent this, as if the user has a rooted phone and has installed apps to overide this block or if a screenshot is taken via some apps that project the screen to a PC.

The editor allows cropping images, drawing and writing text on them as well as add decorations.