In any case, should you, as a technology leader, care about this anymore than the other zillion product launches that purport to make your users happy and productive and your company a raving success?
The answer is, probably yes.
The Case Against
They might have a new CEO with a fresh vision but it's still Microsoft. They've sold the collaboration vision in many packages (SharePoint, Skype, Yammer, etc.) in the past and after navigating the licensing matrix ("so you're saying I need an E3 for all my users + IW add-on and a subscription to US Weekly to get this feature?") you found that adoption wasn't what you hoped, and to do it right you needed a partner (cough cough Gravity Zero).
Sure, that's a bit jaded. We kid because we care. We love SharePoint (when done right), Skype is helpful, and well let's leave Yammer out of this for now. But the point is, we've heard the hype before.
The Case For
While not perfect (remember it's still in preview and not officially launched yet) it's a simple chat app that works on all operating systems and devices (the mobile client is arguably better than the desktop). The real bonus is that not only can users chat with their team members (like Slack, Yammer, or um...email) but they also have easy access to files, notes, PowerBI reports etc. You can create additional custom tabs and more canned ones are expected in the future.
In short, it's useful and simple.
If you are on Office 365 (and millions of us are), the cost is nada/zero/zilch to add this. It's not just that there is no extra licensing cost, you don't need a partner to help you. (Don't worry we can help you with other things.)
Teams might be the gateway drug to get your users off the DropBox habit they have behind your back. How many of your files are floating around on the web for former employees or vendors to see? (I guarantee the number is > 0.)
The Teams experience is simple and kind of immersive, it's just easy to add or open a file right there. In the past, users said "yeah I could upload this to SharePoint but I have this folder on my computer (DropBox) and all of my friends have access to it so I'm good, thanks." With Teams you actually make it easier for the user to do the thing you want, which is keep the content somewhere that you can secure and manage.
Worth a look
We've been using it at Gravity Zero. We've also done so many collaboration projects over the years. So many that we've gone past hype, past jaded, and now sit comfortably in the spot of feeling like we know what works and what doesn't (hint: it's never features, it's always usability).
If you are on Office 365, it's worth paying attention to and considering a rollout.