I've been using my 10" Lodge Carbon Steel pan for about 5 weeks now and am happy with it. I used it to cook a few pounds of bacon over the first 3 or 4 uses after an egg stuck fairly badly the first use. I used butter on Med-Lo for the egg but it didn't play nice. Works great ever since. Eggs, fish, chicken, burgers, Kielbasa w/maple honey glaze... it all cooked nicely and cleaned up easily (except for the sugary glaze). It heats evenly (as tested by boiling 1/4" of water and watching the bubbles) and in far less time than cast iron. I've been using less heat than I think I need and it seems to be working out. Plenty of preheating time is key, just like cast iron.
I fully agree with CruiserDrew in post #33 and treat all my cast iron/carbon steel like this except I use vegetable oil from a bottle instead of spray canola. I can't see there being any real difference there, though.
I haven't used the pan in the oven or on the grill yet.
I have the 10" and it is definitely measured across the rim. The center is about 7.5" across. I think I lose about an inch compared to my got-to teflon pan. I will most likely get the 12" model before long - haven't needed it yet cooking for 2. I actually might skip the 12" and go to the 15" since I have a few 12's already and I usually find that I need more room if I have to use them.
I don't plan on ditching my teflon pans yet and having this one should make them last longer. Gotta keep something around for kitchen guests to use

. Not sure about how my regular steel pans are gonna play out.
Thanks to RUSTY for clueing me in to this pan. I've still not seen one in a store.
--john