Help Me Decide

After seeing your other coins, the young Caracalla is more attractive since it is more different from the one you have than the others are from their match. If you want a second Elagabalus, perhaps you want one with the horned portrait. A second Septimius might be an Eastern mint coin. Your Postumus is earlier and has some silver look so a bronze one like the coin under consideration is a decent choice but I might look for a reverse that is not a figure striding to the left. A lot of this depends on whether you are aiming to 'grow' into a collection of several thousand coins (in which case you buy what is available when it is available) or trying to make the collection an overview in as few specimens as possible. The only wrong answer is one that reflects our opinions rather than your own.