I have casted a 3D (the longest type) of their new speylines,in the 44 grams weight (supposted to be equal to a aftm 10/11 class, with a head of some 70 feet ( 24 meters).
Being a person mostly casting underhand - scandinavian style with shooting heads around 13 meters, but who also has some experience with the fine SA XLT spey and the RIO windcutter (not a long line in your terms, but though...), I must say I am really impressed by the Snowbee line. It was very easy to get accustomed to, and performed very well when I tested it on still water. It was also for me very easy to shoot quite some distance. Even on long casts the line rolled out very nicely.
The head part is white while the shooting line behind is light green, so it easy to know where your line are.
I cant say anything about its durability, but my experiences with its performance is very good and I would recommend you give it a try if you can!
As said on another post the line comesw ith heads in different lenghts, and maybe the weights could have been slightly reduced on the shorter versions (1D and 2D) to have them even better adapted to one rod class. To me it would also be nice to have known the full lenght of the line - as on the RIOs and SAs (I dont know have far it goes!!!)
Good luck.