Aside from the fact that Zen seems to hate the 510 (can't say I blame him, I think the P3 is more solid), maybe it was a sales thing as well. Provape seemed to run out of the various flavors but My Baker never ran out of the 510. I hate to sound elitist, but maybe the masses of istick/kanger/other $35 chinamods won't pay north of $80 for a tank, but those of us who have invested in Provaris will. I guess I'm an elitist.
I don't regret buying the 3 (soon to be 5 I hope) Kabukis I own...one of my peaves with the Kanger subtank was that it would almost always leak, whereas I have only had a couple of bottom leaks from the Kabukis, and I attribute that to the coils. I for one am OK with paying more, if for that reason only.
I eagerly await the Ti tanks. If I don't manage to grab at least 2, I will be............displeased.