I think it depends very much on the manufacturer of the drive:
My LG 48x CD-RW is very quiet and ultra-reliable.
My 16x Pioneer DVD slot drive is also very quiet and ultra-reliable, and reads files at lightning speeds.
My 24x Cyberdrive CD-ROM for my A1200 is ultra-reliable but not as quiet as my LG and Pioneer drives which are much faster.
I have heard some cheap/unbranded drives that sound like Concorde taking off!
