You're not bothered by the "openness" of the back?
Refund/exchange it dude.
Pfftt... so let them look. I make noises, voices, actions in public.
You should be okay. The disintegration issue has only been reported to occur in Hasbro Megatron and not Takara; it seems that Takara used better quality plastic than Hasbro on their Metals Megatron. Also the deterioration occurs in the brown plastic, not the clear one. It seems to suffer from similar frailty as the gold plastic used in some G1, G2 and BW toys (e.g. Slog, Bristleback, Pyro, BW Grimlock etc.)
Ah yes, I have two of those sets.(one opened, one sealed) -- yours is already of the box anyway, so you might as well open them. I don't even know if keeping the sealed in box makes them worth more (is there much demand for these cards?)... I just happened to have two sets (they were pretty cheap when they came out, and I 'em for free anyway
) so I opened one box and keep the other sealed.
I'd open them if I were you though. Buy some nice collectible card-sleeves and a ring-binder folder for storage/display.
(that's where I keep all my cards including JP tech spec cards) They give you some cool bits of info like certain characters' height, weight etc.