Were you using the same HipChat that I was? I recall the engineers at my employer (including me) clamoring to get off HipChat and onto Slack. Search was terrible, integrations/automation were clunky, and it was difficult to post code into chat. Slack was a breath of fresh air when we switched.

Also, I think Slack's threads are useful. You can have channels where you just post a single message for your question/issue and then have people reply in a thread, so that messages are naturally grouped together by topic instead of being a firehose of interleaved messages. Combined with good search, this makes Slack more of a valuable knowledge store than just an ephemeral chat tool.