Gekkos and Shagohad are not Metal Gears. My favorite is the fully upgraded ZEKE with full A. And peace walker body parts. It can take down Rex since it can outmane uer it and jts smart enough not to stay in range. Plus you can program it to say whatever you want in the PSP version.
Look at you, soaring through the air like an bird... Piloting a blimp.
REX is just too classic. The sense of awe when you first go into the hanger and have to cross over the top of it is great. It's also a really clever way for the developers to give you a real sense of scale before the fight. Absolutely awesome.
Of course, it's too bad they made you go through a bunch of ridiculous backtracking right there with the PAL cards and ruined the pacing just to be faithful to that stupid plot device. Grrr... (-_-; )