My Ark arrived Friday as well, but I have to return it for an exchange because Mainframe/Teletraan-1 is missing an entire panel.
It's lacking in playability -- there's no weapon, gun turrets can't turn. Mainframe's posability is limited by the huge panels in the back. I own no other Titan class City bots for comparison, but it's far less complex than Titan combiners (Devastator & Predaking). So Hasbro could've/should've packed more gimmicks into the Ark IMO. But seeing that I bought it at the Commander price, I'm not complaning. It's heavy (about 9 pounds) and got ratchet joints everywhre that count.
Too bad I have to exchange it and who knows when I'll get the new one. Hope I can get it in time for Christmas.