It all depends on how much you shoot and how much time you got to reload!? do you plan on loading for rifle later down the line? sdb(square deal come with its own dies only for that caliber(you cant load riffle) you wonna load for, its small from what I seen and the RL550B is a manual indexing press(meaning you gotta turn the star by hand),on the 550b you can load rifle and there is an optional casefeeder but it DOES NOT feed rifle and uses standered loading dies as the 1050 and 650.the 650 is auto indexing press(meaning bull down the handle it turns the star each time you pull the handle)If you decide to go with the 650 get it with the casefeed or its just a auto indexing 550! the 650 comes with a powder check system also the sdb, rl550b, and 650 come with the Dillon no bs warenty great costomer service and the 1050 is a beastyou aint ready for that!lol... as for me I like my Dillon RL550B I am loading for 40's, 45ACP, and 44 magnum and the conversion kits are fast to change over. Dillon is truly the cadillac of all presses you get what you pay for and some! good luck on your choice you will love anyone that you decide to get