well, i have an Air 540, so i can tell you some stuff about it
it's pretty nice, but yes, other than the grill itself, the top and front panels are both completely plastic. it seems relatively smudge resistant, so that is good. the window is okay, i am quite careful around it, so i cannot speak for its scratch resistance. i do have a H110 in the top as intake(not something most people would do, i am guessing.) and it does get dusty, but before i had this i had nothing in the top, and i didn't notice any excessive amount of dust getting in. i haven't really noticed the hard drive cages rattling/shaking, but it did throw me a bit when i noticed the holes in the bottom of the thing. my only real regret is that i didn't realize that i could've gotten a MATX motherboard and used the 240 ;p