Got the Series 1 and returned the Series 0 that I bought from BB for $220
The S1 is so much faster it's crazy
OS3 made the S0 faster, but now the S1 doesn't drop any frames or lag when opening apps. Raising your wrist brings on the screen a touch faster, plus Siri is a lot faster and everything feels super smooth.
For example, on my S0 when I pushed down to change my watch face it would take like a second or two for the taptic feedback to kick in, sometimes even lagging for longer. Now, it's instant when you press down