I use slack every day, it has everything I need as a dev to communicate with my team. I have used other products that compete with slack but it doesn't come close to the experience I get on slack. The most recent feature that I really love is on mobile, catch up helps me get up to date with stuff that happened after I clocked off the previous day without having to physically click on each thread!
Slack is great!
I use it to track my development tasks, what I like about it, is it's simple and straight forward. I'm an indie dev so using something like jira is way too much overhead, superlist makes this easy and straight forward. It also works for many other different kinds of lists so I can use one app to do it all.