Its totaly not worth it. I bought the 1x superdrive for my iBook and it was slow and i didnt use it ever. Just buy a firewire enclosure and get a dvdrw drive for it..
the g4 ibook upgrade is 2x, it may be better if you were up to doing the upgrade yourself to buy a powerbook super drive upgrade and put it in your ibook, it's a little hard to do but you would save a ton of cash.