You should do some demos.
Antler and Custom X have one thing in common, both are high end boards with top technology in the burton line. Ignore the mystery, vapor and so on, only douchebags (like me) own those boards.
You want a custom X if you are mad about edge hold, like to rip groomers at 50 mph, and carve the hill into shreds. You probably want diode bindings to go with it. Steeps, technical riding, bring it on. Or you're just a crazy guy who loves to bomb it.
You want the Antler if you want a lightweight responsive board that will be a lot of fun on the hill and can go in the park a bit too. Good on soft snow but not a powder board You likely will pair it with genesis bindings.