LiteOn / 5- & 6-chip series

Concerning the read/write quality…
What’s are the differences between the Mediatek 5
and the Mediatek 6 chipsets? Do they perform different?
What would I get when kicking my 48125w and buying a
newer writer (based on the Mediatek 6 chip)? And when
will the LiteOn 52x/32x/52x be released?

I bought the new 52246S a few days ago and the first thing that I discovered is that it is much less loud and that a cd-r I used before (which gave me about 3% damaged sectors at 48X, tested with cd-speed from nero) does not give me any errors anymore at 52X with this drive.