I've got two 510s, and the old one (almost 5 months now) is still sporting the original atty and one battery from the original pair. Yet to have an atty burn out with 'em, and for that reason alone am very impressed with the 510. Vapor production, to me, is still better on a well-tempered penstyle, but as others have noted, I'll go through 2-3 penstyle atomizers a month and as many batts or more, so the endurance (and consistency) of penstyles leave a lot to be desired. I think you get better flavor hit from a 510, as well. Seems to carry the flavor onto the palette better than do penstyles.
Batts on the 510 seem to have a decent shelf life, but I can suck one of those puppies dry in an hour or less, which isn't bad, I suppose, since they also charge quickly... but still, switching batts so often is a nuisance. Would like to try a larger battery assembly of some kind with a 510 atty.