Got one too. Amazing little device. I'm staggered that it got such bad reviews for it being such a nice polished product. I'll say however that it's probably made for men with larger bodies. If you're a skinny little dude it'll feel clunky on your hand. But the notifications are awesome now. New email? It'll notify me and give me the icon. Press the icon and I get the full email right there on the watch. Same goes for practically any app (now that the update's been rolled out, you can activate notifications for pretty much everything, and it's not just previews either, but full messages/emails show up).
I installed the null rom but honestly it's a bit of a waste of time because running Nova on a screen that small just doesn't make sense. Samsung did well to make a UI just for that screen size and it's a joy to use.
The battery lasts several days, not one like was mentioned in reviews. The UI has no hint of lag whatsoever so, again, I have no idea what the reviews exactly tested but I'm going to assume that the recent updates fixed it up a lot.