Sony DDU-1621 is not really bad due now of 20% cheaper price !
It's one of the noiseless DVDs in the market ,supports most known DVD formats you can easy find this moment ,very fast DVD ripping ,and CD audio ripping plus very well DVD-ROM perfomance ! -Also Digital audio out, combines excellent if you have good soundcard-maybe better of all market DVD-roms (depends also on your computer config)
It's OEM of BTC BDV316B : read some info about it:
http://www.cdrinfo.com/Sections/Article ... undup+Vol2
The only problem is high seek times in acessing Data CDrs writing >24x (and very common today) -Sometimes not possible at all ! -
Choice is yours if you dont mind this !
Toshiba SD-M1712 is new and a little expensive as every new model in the market . An opinion of this you can find :
http://www.cdrinfo.com/Sections/Article ... +DVD%2DROM
but you must wait to read users opinion before buy it !
Finally for Liteon choice ,try searching forums .
Older model LTD-163S (without discontinued DVD-RAM support)
looks maybe better in perfomance than LTD-166S as users opinion wrote ,and it's cheaper now !