Our team tried out Slack, but the Mac app isn't native, just a rather weak wrapper around the normal web page. And the web experience just isn't as good as HipChat.
Also, no in-app voice/video integration that I could find. HipChat's one-on-one video is great, although waht I really wish for is conferencing built in. Google Hangouts is just too annoying to set up (first it pesters me about signing up for Google Plus, which I don't want, then it shows a blank screen with a "start a hangout" button, then it opens a GH video in a separate window, which is just stupid), and doesn't have a desktop app.
Also, no in-app voice/video integration that I could find. HipChat's one-on-one video is great, although waht I really wish for is conferencing built in. Google Hangouts is just too annoying to set up (first it pesters me about signing up for Google Plus, which I don't want, then it shows a blank screen with a "start a hangout" button, then it opens a GH video in a separate window, which is just stupid), and doesn't have a desktop app.