That's easy, the 470 NE. Ease of obtaining brass--it's a helluva easier than trying to get any 450 NE brass of any flavor. Ease of getting bullets nowadays. Granted the 450 NE's can use 458 bullets but if you don't have brass because of limited availability, then you just have a really fancy and expensive club. I've known of a couple of guys who had to replace their brass and couldn't get any in quantity (100) or more. A lot of 450 NE brass is advertised out there but if you hit at the wrong time, you have to wait a year or two for the next run. Besides all that, the 450's are really expensive. I've gotten 470 NE brass whenever I get the chance and will hoard them.