40125S or 40125W

I am planning to buy a Lite On writer and have some questions for you guys. What is the difference between 40125S and 40125W? I can’t find 5W model at stores. Which one is better 32123S or 40125S?
Thanks.

40125S is better.

Or get 32125W or 40125W if they are availible.

I am a little bit of confused with these drives.

I have heard problem about quality issue on P-cav burning with LiteOn 40x drive. Which one actually has the problem? 40125s with unofficial firmware or 40125w, maybe both?

probably both have it with some types of media. As long as the media is 40X cerified there normally is not a problem with writing at 40X.