Yea your right about the 3520.
The only info on NECs webside was in a pdf for the 3520 but I took a closer look now and it's for the 4550 and not for 3520, wrong link on their webside.

Also NEC looks very good for me but I still think about my old LiteOn CD Writer LTR-52246S that is now almost 3 years old and that has always served me very well.
And I think about the troubles I had with my LG DVD Writer to read some of those CDs. Some of them must have a real bad quality at least a test with one showed a quality of 30. I guess that are the ones I burned with 52x.
I'm a bit afraid of using another manufacture to only to see those CD reading problems again.
The new Writer should replace my CD Writer and my DVD Writer so I really need a drive that can also read a bunch of “bad & old” CDs.

I guess I will have to go thru both drives again and see if I can find something special that helps me to decide.

Maybe you can help with another point. I heard that the LiteOns use some kind of special chipset so that flashing them forth and back or putting up original fw in case of an error or whatever is no problem. Is it true? And is NEC also that easy?