Welcome to CDRLabs, Nickmm!
I would recommend that you keep the Lite-On drive. I would recommend this for several reasons.
1. The Lite-On drive supports disk quality checking software like KProbe.
2. The Lite-On drive supports writing at 32x whereas the Samsung only supports 24x.
3. I have heard that the Lite-On has better media compatibility than the Samsung.
If your computer is slow enough that it will have to pause the burn until the buffer refills, having an 8-MB buffer shouldn't make much of a difference. I have heard that having a larger buffer may cause packet-writing to be faster on slower computers, but I really don't know if that is true.