Mine is very flaky. Funny thing is I was missing the way my Pebble worked 95% of the time and meant to ask about this until I ran across this thread. With this, wrist flick is maybe 50%, OR I have to do an exaggerated arm raise motion - I can't just look down and flick my wrist like I would on my Pebble to see anything. Also when it does work, it's slow - there's like a half second where I'm waiting in suspense for the display to wake. Maybe you people that came from the older Gears are used to that and it's ok for you, but with my Pebble I was never waiting - maybe it's due to the fact that Pebble is only turning on the backlight from the sensor, as the display is on all the time.
Which brings me to my biggest frustration. I had hoped that somehow an AMOLED screen could be set up to be always on with just the basic info while still saving battery (like active notifications on the Moto devices). I hope that somehow there's a way to work around this and have a simple info display that could be always on (no colors/animations, just white text on the black background to save power). If i needed to charge every night, that's fine. I'd rather have that than look like/feel like an idiot shaking my wrist around and still not getting it to wake up. That's one of the reasons I returned the Sony smartwatch last year.