As a first time Mac and Trackpad user but a long time and heavy iPad user I found it very intuitive and natural.
I don't think that it is natural to have reversed scrolling on a touchpad or mouse. I like it on my iPhone and iPad but I hate it on Mac OS X. It is just unnatural and I have it disabled. In fact, this is the first thing I change when I install Lion.
I don't know why they switched it up for no apparent reason
The big problem with Natural scrolling is inconsistency.
If they decided to make it Natural by default, then why are 3 finger horizontal swipes to the dashboard or other desktops set to the 'unnatural' (opposite) behaviour?