I wear a moto360 everyday since october, and I really like the "hardware part" of the watch (it looks good and feels nice).
But, the software (or whatever it is), is a complete mess.
The UI (card display, gestures) is made for square screens, not round ones.
The voice control either doesn't work because of my accent/noisy surroundings or it makes you look like a very very strange person.
For a long time, there was an issue that kept the time displayed on the watch's ambient screen from updating (so you would get "jumps" of several minutes when the watch activated).
I could go on for a long time, but I think you get the idea: it is just not a finished product.
My LG G used to be awesome, but recently my Nexus 5 has been crashing all the time, and removing the Android Wear app and unpairing the watch completely fixed it. (plus the phone has much better battery life now it isn't crashing all the time)
So yeah, wear on flagship devices purchased straight from Google, not so good at the moment. I'll try it again in a few weeks to see if they've fixed their QA problems.
I could go on for a long time, but I think you get the idea: it is just not a finished product.