I got these too last night, and picked up UW Superion from tfidownunder too. All I can say is Rook is ... terrible in my opinion. Terrible robot , wish for proper hands, terrible leg mode which is a shame because I wanted first aid as an arm... like I said in UW Guardian thread I wish I was getting it rather than hasbro... and even more so last after last night... (Anyone wanna buy complete CW defensor? >_<).
What I can say though is it's more stable by far than Menasor, though I havent done a hip ratchet fix on motormaster (shouldnt have to), Blackjack is held on by bluetac, and his feet are bluetac'd down, after my very slight wife walked into the room and her sitting down sent a gentle tremor through the floor, making the bookshelf shake almost unnoticably, but it was enough for menasor to tip a little forward, blackjack fall off onto the floor 6' below, and the weight shift tipped menasor backwards (lucky for the wall, and no small parts to fall off behind the shelf).