The eTAU108 has 2 MB cache!
Most BD drives have 4MB, rarely 8MB, despite 16MB could easily be possible.
The SE-208DB has only 1 MB. Even SH-224 has 1.5MB, SH-S223 2MB, SE-S224 has 2MB.
Additionally, the LiteOn and SE-208DB perform nearly desktop-ODD (S182)-like writing quality on discs, if the USB port supplies 5V/2A. 5V/1A can lead to trouble on old devices.
The used eTAu108 only cost me €3 on eBay. Really priceworthy, considering that the new SE-208DB costed me €34 in 2014. But the SE-208DB has a much more advanced error management performance, especially for DVDs.
But I must say, the eTAU108 is excellent and really portable.