I agree about warranty for rebranded stuff, but this is originally branded parts, just sold in a ‘white box’ labeled Emprex. There’s nothing Exprex about the drive–no custom firmware, etc. It’s not like Buffalo, etc. where they do some customizations.
Their AD-7200S drive is an actual AD-7200S. Their AD-7190S is a real AD-7190S–which happens to be rebranded by Optarc from a Lite-ON model–search elsewhere in the forum for that story if you’re interested.
Warranty on a $20 drive? blink Uhh, okay. You have to ship the drive back to the manufacturer to get a replacement–assuming they’re willing to RMA it (see my early posts on my Sony 710A experience if you want the painful story). That shipping, alone,
may cost you the price of another drive. Why bother? Sure, if you paid $100 or more on the drive, it might be a concern, but, for disposable consumer electronics? The cost/benefit analysis of that does not work out. But, that’s just IMHO. YMMV and all that.
Short version of Lite-ON/Sony history: Sony drives were Lite-ON drives with customized firmware. Then the lovers had a falling out and Sony used other drives–some Benq drives, etc.–then Sony fell in love with NEC and formed Optarc. But, the relationship couldn’t produce ‘offspring’ fast enough to suit Sony, so they were forced to rebrand some Lite-ON drives (AD-7190 amongst possibly others). There’s a lot more to the story, but that’s the broad strokes.
I only mention that to somewhat refute your ‘lite on is a cheapie sony in disguise’ comment. There are no sony drives. All of them are rebranded drives from someone else. Again, someone please correct me if I’m wrong on that.
So, OP, please let us know just what you’re looking for in a drive and we’d all be glad to help you with both advice and education. But, we’ll talk amongst ourselves until you get back.