i've heard really cool things about CG offices. i dunno that much about the company, but when it was first getting started, i heard all sorts about how the owner was, like, a ted turner kinda rich guy, who really loved comics and just wanted to spend whatever it took to get his own comic company. he set up a great environment with the ideal ___ whatever (lighting, pencils, studios, etc), and used all that to get the great talent.
sounds like a pretty cool shpeal to me :)
i cant speak for marvel, but the best way to describe the dc offices:
imagine a standard office building, with a big room -- all the cubicles on the inside, the offices lining the outside walls, yadda yadda. every door has a name tag and there's a local copier and office station, etc. now imagine some saturday where the office owner let 1,000 kids run around and decorate the place themselves. painted on the walls, put up every super hero poster they could find, left their toys out on the shelves, put big cardboard cut outs of superman and stuff on the ceiling, etc. even the door name tags are shaped like comic book word bubbles. very fun place.