I have skied both on and off piste.I own a pair of Sultan Legend 85, had a pair of BW ( 2012) ( I have returned them) and had the chance to ski a pair of BW ( 2013) for a full day at Jay.
First, if you decide to go for the BW, go for the 2013 because the early rise on the 2012 is too agressive and I find it way better on the 2013. But it is still a big early rise so I would go for longer rather than shorter... Me (6' and 200), I was ok with the 180 and even ask myself why do they stop at 180?
It is true that the BW are lighter than the sultan, and they do feel ligther and quicker under the feet. So, I had much more fun in the woods and the moguls with the BW (2013).
For carving, sultan are just ok but the BW were really fun ( the 2013) after a couple of runs because it took me some time to carve with the early rise ( You have to be a lot more on your toes...)and even then, I still don't like too much the early rise .They are ok even where it is icy... I hated it with the 2012...The early rise is too agressive: it doesn't bite and is unstable at higher speed.
Off trails, that is where I saw the biggest difference between the 2... It was a real pleasure with the BW... I had the feeling to digg with the sultan and float with the BW.
The downside of a lighter pair of skis is when you have to deal with piles of heavy snow... You get bounced all over with the BW but the Sultan are so stable!!! That is why I call them my tanks!!!
So that's it, I liked the BW 2013 a lot but not enough to buy it... I have prefered the Kendo ( 2012) over it because I find it to have the best of both the BW and the Sultan. And the 2013 shoud be even better with a very subbtle early rise!