Do some reading over in the Plextor forum. Several people there own both drives. I was thinking about a Plextor 716, but I can't quite get over the price. Even with the $30 rebate (I hate rebates).
The LG4163 looks much more interesting to me. If it could do quality scans, I would have already bought one. The price is down to $68.49 delivered from Newegg.
On the other hand, there are a lot of neat things to play with in the Plextools package. If it just didn't cost so much...