Hi and happy Easter,
This hybrid was a special request and many thanks to David. I was weighing durability versus design and it was pointed out that because the 501 threads are rather fine, stainless might be better for the atomizer post. Likewise, the battery cap itself will get removed a lot, especially if you use LR 510's. Meanwhile, the brass button section has thick threads and does not get taken on and off as much. This is both aesthetically and practically speaking the best of both worlds.
Nobody who owns one of these babies has been had, though. It's kind of like, which Rolex do you prefer?