I really liked slack but in the end we went for hipchat for a two main reasons. 1. It's 25% of the cost (although that has now shifted). This may not be a big

I really liked slack but in the end we went for hipchat for a two main reasons. 1. It's 25% of the cost (although that has now shifted). This may not be a big deal for small teams but if you want to have 100 users on either service, the difference is between $2,400 a year or $9,600 a year. That's a big difference. 2. Hipchat has a self hosted option in the works which should be available within a month or two (per them). This is essential for any company that deals with potential PHI on their IM systems. Slack says they plan to offer a self hosted option but it's a long way out. Those are two things slack just couldn't overcome, beyond the fact that I generally liked slack better (it's prettier, much better message searching, better integrations, etc). The fact that hipchat also has voice chat is a big plus too though we've not found it reliable. Presumably at some point it will get better though and make it a more valuable feature.