I like that you can join multiple conversations at once without having to switch between apps or tabs! It's easy for me because of how intuitive it is.
There are no downsides as far as i know but there could be some features we don't have access too yet (like more themes). If your looking for an app with tons of different chat groups this isn't really what they're about though so if thats not important then go ahead and give them a try. They do host many twitter chats which makes getting involved easier than ever before.