Much as I dislike Samsung and their preference for using the cheapest of plastic I don't see myself paying $1000 for the Asus Vivo Tab and since nothing else has the same features I think i'm leaning towards the Ativ.
Yeah, I'm not sure what makes Asus think that their Vivo Tab by itself worth $799, and the keyboard dock worth an extra $200. I mean, I know it has an extra battery in it, but it shouldn't cost $200. Too bad, because I like the idea of the extra battery. Not only does it extend battery life, but it'll make the combined keyboard + docked tablet feel more balanced like a laptop. It won't be prone to falling over backwards.
And again, $799 for the tablet only? The Samsung SmartPC WITH the keyboard is $50 less!
The HP Envy X2, which I thought was expensive from the start, is actually still cheaper than the Asus Vivo Tab + Keyboard. The Envy X2 is sold only with the keyboard dock I think, but the base model ($849) may start with only 32GB of storage and probably doesn't include the stylus. Also, no one seems to be sure what digitizer it's using (Samsung and Asus are using Wacom).
Meanwhile, the Lenovo ThinkPad Tablet 2 and Dell Latitude 10 are more of in their own category (aimed at business). I was confused by this before, after reading a thread somewhere else, it seems the Lenovo may actually start at $629, but only have 32GB of storage, 1GB of RAM, and no stylus. I'm not sure what the $649 price I've been hearing is for, but for $699, you can get it at the Microsoft Store and it'll have 64GB of storage, 2GB of RAM, and the stylus included according to their description. Even so, the Samsung is on sale at Staples for $599 right now.
Moving on to the accessories for the Lenovo--Keyboard with stand is $120, and that is not a dock. I think the keyboard connects via bluetooth, and the dock is a separate item that I'm not sure how much it costs. Hopefully the xx% coupons Lenovo offers sometimes will help bring the price down.
The Latitude 10 seems to be available for pre-order on Dell's site for $699, but right now until sometime in January I think they're offering $50 off, for a base price of $649. I don't think there's a keyboard for it, but there is a dock available for a whopping $145. And that is a dock WITHOUT a keyboard. Seriously, if these OEMs aren't getting you on the tablet price, they're getting you on the accessories. The stylus isn't included either, it's an additional $49. This is the only tablet that offers a swappable battery. It comes with a standard 2-cell battery, but you can get a 4-cell (twice the battery life?) for $80.
TL;DR - So for Lenovo vs Dell, if you're getting the tablet only, probably a slight edge to the Dell. You're both getting the same features for $699 (64GB storage, 2GB RAM, stylus) but the Dell you can replace the battery yourself.
And for the hybrids (Samsung, Asus, HP) the Samsung seems to win it on price. It's $100+ cheaper than the other two whether you're getting the tablet only, or tablet + keyboard. It does weigh a bit more, seems to lack NFC and Samsung does use plastic that feels... sort of cheap (but it doesn't mean build quality is poor) but it is priced right IMO. Plus, it's the only one available right now, although it is hard to find.
I'm still hoping the Asus realizes their mistake and drops the price.