When comparing IMO vs Snapchat, the Slant community recommends Snapchat for most people. In the question“What are the best messaging apps for iOS?” Snapchat is ranked 16th while IMO is ranked 20th. The most important reason people chose Snapchat is:
All Snapchat communications disappear after they've been viewed. It creates more interesting conversation when you don't have to worry about consequences as much. Additionally you can doodle on photos.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Video call support
Pro Beautiful User Interface
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.
Pro Easy to switch between conversations with tabs
Tabbed chats make it easy to switch between conversations
Pro Lists and chat histories are searchable
Both your buddy lists and chat histories are searchable.
Pro Accounts can be linked so you don't have to sign in to several accounts
Pro Push notifications
Pro Concurrent sessions
Concurrent sessions allow you to be logged in on your desktop while also being logged in on your phone.
Pro Chat groups
Pro Allows sharing photos, videos and texts that self-destruct
All Snapchat communications disappear after they've been viewed. It creates more interesting conversation when you don't have to worry about consequences as much. Additionally you can doodle on photos.
Pro Includes news
Snapchat includes a Discover page (accessed by two swipes from the right side) where curated list of news and entertainment outlets can put up news from their sites.
Pro Does not get in the way of what it's designed to do
Snapchat is first and foremost a way to share photos so the first thing that the app presents the user with is the camera enabled and ready to take photos. Once photos or videos are taken, it's possible to caption them or draw on them.
Cons
Con No support for third-party instant messaging networks
On March 3, 2014, IMO will start discontinuing support for all third-party instant messaging networks.
Con Security concerns
In 2013, Snapchat was hacked. As a result phone numbers and usernames of 4.6 million users were published online. That happened after concerns were raised by a security firm weeks before that Snapchat dismissed. Other security concerns were pointed out to Snapchat throughout 2014 including ways that the service could be used for DDOS attacks and how their anti-robot measures can be circumvented.
Snapchat has since implemented two-factor authentication.
Con Non-intuitive UI
The UI space is well used but you'll likely miss a few messages until you understand of the UI works; it's not like the average mobile apps.