I'm back.
I've had the 510 for almost a week now, and maaan have I been putting it through its paces. Thought I'd give you all my "official" review.
First off, e-smokey treats was great to buy from. Super fast shipping; everything got here in two days and it all worked. The kit came in a nice heavy box with a few extra cards to pass around to friends. No complaints at all there. Shipping: A!
The 510 itself is so much more sleek than I thought it would be. It's only a bit larger than a regular cig, and I like the wide gold band e-smokey uses on theirs. The weight in the hand is nice, too -- it balances in my fingertips much like a real cigarette would, though I choke up on it a little to avoid the button. Looks: A!
On to what it's actually like to use this thing. Straight out of the box, I was iffy for a little while. I was getting one heck of a throat hit, but hardly any vapor and the taste was awful. I tried vaping off the primer for an hour or so with no change. When I finally gave up, blew out the atomizer, and dropped a little vanilla on it -- wow! Complete turnaround. I finally knew what everyone was talking about when they went on about the vapor production here. The thing I've finally figured out with mine is that there is a real learning curve on what my 510 likes. The atomizers seem to clog a bit more often than with my 901, but once you learn how to *not* overfill the carts it chugs along like a little champ.
The 510 has made me cut down on vaping, because I'm actually satisfied after a few minutes with it, just like a real cigarette. This actually kinda sucks when I find a new juice I like, because I'd like to keep playing with it, but it just becomes too much. I *have* to put it down here and there -- which is a good thing, believe me! I was well on the way to having my previous e-cig permanently attached to my face.
So, on throat hit and vapor: "A" overall. I can smoke my 510 on a windy day and still see the vapor! I do go through slightly more juice (I think) than I did with other models, but it's not nearly as significant as I was worried it would be. Even if it was, I wouldn't care. Gotta pay for performance here.
Batteries: This isn't much of an issue for me, since I have the passthrough and the charging case. I was careful to season my batteries exactly as the instructions say -- 8 hours on, 20 mins vaping, back on the charger for an hour -- and honestly I've only had a battery run all the way down on me once so far. I've been out at parties absolutely flogging these things, letting my friends try them out and chain smoking, and they still seem to last 3 hours + for me so far. Definitely not the best, but I'm also never worrying about whether my batteries have run down accidentally in my pocket, or have died again from juice leaking down into the non-sealed auto batteries. Friday night turned into one of those super long, up till dawn kinda nights way out of town at a friend's house, and never once did I have to worry that I'd be searching around for an outlet to plug in. Those embarrassing days are over! So battery life: C, but with a ton of extra credit for the accessories.
Last thing for me, taste: I definitely get a more "complete" taste from my 901. On the 510 I can tell that my caramel is caramel, but that's about it. It doesn't bother me at all, but if you're one of those super-tasting afficianados (I'm looking at you, Crazyhorse), you're not going to be happy. There's not a lot of subtlety to the 510 that I can taste. I'd give it a B-.
That's all I can think of to grade for now. After several days of just beating the crap out of this thing, it has stood up to every test I can throw at it. It's consistent with what I can expect from it every time, it works every time, and the hassle involved is practically nil. I've found the model I'm going to stick with.

I just wish I had found it sooner!