It has the ability to share windows (awesome!), but there's a persistent watermark that's annoying and covers stuff up. Quality is often worse than Skype, which means waiting a few seconds while it clears up the text.

It has crashed and/or disconnected more often (never thought I'd say that, it's kind of hard to beat Skype here, but it has). Acceptably stable still, but it's still an annoyance.

For communication purposes, it doesn't have real persistent chatrooms, so we lose history if someone doesn't check in for a day or so. Same with searching the history.

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All of which means we still have to resort to Skype for some things, at which point the annoyance of having multiple simultaneous communication systems outweighs our annoyance with Skype.