I don't have one. But I've seen them up close and they are pretty cool. Receiving texts and call via your watch. Personally, I don't like wearing jewelry of any kind so I don't wear watches often.
I like my Apple Watch. Would I say it's essential to my daily life? No, not at all. But I often leave my phone on silent because I'm in meetings/classes all day, and it's nice to get a silent little buzz on your wrist when you receive a notification.
I have the Samsung Gear S2. I actually love not having to look at your phone to see how late it is lmao. I usually never wear watches (because I can't read analog and digital usually are ugly) but I've grown used to this smart watch. 🙂 My phone is almost always on silent so it is nice to get a notification on my watch (only for important things like texts, phone calls, agenda). I've disabled FB, Messenger, mails, ... 😛