@socketwench - Big fan of the HLDS BU40N 4K Blu Ray drive. It's been encoding my 4K and Blu Ray stuff like a boss, since it's easily hackable.
Downside: It's bare bones external (no case or DVD program, even), and requires a third party program to encode 4K Blu Ray (I use DVDFab which runs fine through WINE).
It also will NOT play 4K discs without a very specific setup as it's locked to Intel Architecture. The ripper doesn't care, though, and my system will play the ripped 4K file just fine.