full wood is such a bad idea, this on the other hand not so much, and using proper motherboard spacers to mount the mobo to the boards, very nice and clean looking, only cost about 30 dollars to make
i am presuming you are concerned about risk of fire that can burn wood so metal is better?
Well, here is my version: when using metal frame i found risk of shortage and electrocution is risky
Yours look good, but still I'd think I will go for wood.