I canít see how drilled/grooves disks can corrode more quickly, that is determined by the material used in manufacturing and not if it has grooves/holes put in.
I have recently fitted grooved/dimpled discs to my 5 series and not found them to be noisy at all. Not done many miles on them so canít comment on pad wear as yet but for the price I paid it was a no brainier compared to bmw price for 2 piece discs even on their value range.
Theoretically, if the discs arent coated with some asti-rust agent, the surface inside the grooves/holes is free to develop corrosion without getting scrubbed clean by the brakepads. I have no idea if this would be of any significance though, it might impact the structural integrity to the point where cracks develop easier, but again, i simply dont know.