Got mine in the mail yesterday. I thought the envelope was empty at first! I guess I was expecting a new switch housing, for some odd reason.
I had bought the #60 O-ring, which was a LOT thicker than the new O-ring PS sent me. After careful consideration, I decided to go with the new O-ring PS included in the upgrade kit. I'm having trouble putting into words WHY i decided the PS O-ring feels better, though. Because it's thinner, there's 'more button to press' (if that makes sense) and it feels like there's less chance of it going off in my pocket.
Now, for the stainless steel contact posts.......those simply KICK ...!! I would recommend ANYONE with a V1 or V2.0 to get the upgrade kit for these, even if the kit WASN'T free! With the aluminum posts, I always felt like I had to take a primer puff or two.....but after switching to the stainless posts, and using the same atomizer and the same batteries (no recharge) it feels like the INSTANT you activate the switch, you are at FULL VAPING CAPACITY, every time!!!!
I LOVE IT!!!!!!