Completely different, regular is more powdery, floral, Special Reserve on me seems to have more of a tobacco scent with a hint of floral, that's just my impression.
I prefere Special Reserve 10:1, or some vintage Club Royale that I have.
They are different scent-wise. Performance-wise they are pretty much the same. I prefer the regular version where others might prefer the Special Reserve (YMMV). It's one of those that you need to try. It's purely for the scent that I got the regular version. Agreed on the powdery scent.
Special Reserve has that old leather chair that would have been in a men's club where there was plenty of whisky and cigars. I love the stuff. Go with a light hand on initial applications as it can be a little heavy.