I've got a series 2 which works fine for me.
I use it for the daily activity trackers, recording walks, runs, yoga etc
It has the usual calendar, reminders, notifications from messenger, text messages, FB etc.
If you use the iPhone map for directions it displays on the watch and vibrates when you're coming to turnings (only really useful for walking places rather than driving)
You can use it as a remote to take photos on your iPhone.
You can play music directly from the watch to Bluetooth headphones or use it as a remote for music/videos playing on phone.
You can reply to text messages with set responses at a touch or use the screen to write a reply (which isn't as difficult as I thought it would be).
Records my heart rate, records my sleep and it automatically counts laps in a swimming pool (you just tell it how long the pool is).
Some things only work in conjunction with your iPhone in Bluetooth range. Other things work solo.
I've got applepay set up so I can pay for things under £30 without needing my wallet. You do need to make sure you've set a secure password.
And it tells the time. 😀
I love it.