As Albert said TSST drives are Samsung (Toshiba & Samsung have had a joint venture producing optical drive for many years). The TSST ones are just the OEM version and usually have a direct Samsung equivalent.
Samsung's slim DVD writers have generally had very good writing quality. The old external SN/SE-084 drives were very good.
I have a year-old SE-208DB (the TSxx firmware version) and the writing quality is excellent (especially CD-R/RW) - almost as good as my SH-S202/3 drives. Scanning performance is similar. An internal SN-208DB is available.
But the very latest Samsung/TSST drives are not so good. The later SE-208DB drives with MFxx firmware have significantly worse writing quality (in my experience), also the SE-B18 drives. And I have a Transcend external slim drive which uses an unknown Samsung drive (probably SN-208FB judging by the 512KB buffer) and has difficulty writing the last 300MB of DVDs - high PIE & PIF (although the Transcend firmware may be a factor).
Many of the Optiarc slim DVD writers are rebadged QSI drives. I had one (AD-7580S ?) and it was awful. Check Liggy & Dee's site for information on which were the genuine Optiarc drives.
If you want a Blu-Ray writer I would also recommend Pioneer. I am extremely impressed with the writing quality of my Pioneer BDR-TD03 on all disc types. It can outperform most of my full-size drives. It is also noticeable better made than my other slim drives. The BDR-TD03 is an older model, but the current Pioneers are probably worth trying. No scanning though.
If you want a slim Blu-Ray writer which can scan, the only option is Samsung/TSST. The earlier SN/SE-506AB & BB drives looked good in terms of writing quality. But the latest CB version had a serious issue writing BD-R discs at 4x(?) speed, which I don't think has been fixed by a firmware update.