"Burn-Proof" is a technology developed by Sanyo which eliminates the problem of buffer underruns. Buffer underrun occur when your cd writer is writing faster than your cd reader can read data from the cd. "Burn-Proof" basically allows the cd writer to stop and wait for the reader to catch up and then continue writing again.
Personally, I think "burn-proof" is a must with IDE drives. That way you can burn at 12-16x and still run as many applications as you normally would without having to worry about messing up your cd.
In my experience, the yamaha 16x10x40 is a good writer without the burnproof technology (due to the 8 meg buffer). However, it sucks big time as a reader. Plextor drives are not only great writers, but in my opinion, the best readers out there.
So, in conclusion, go buy yourself a plextor, you won't regret it.