Bob, do love using (or rather did for many many years) the 120' DT lines for spey rods. For short/med range casting they were, and still are, the cat's meow. For line control, they still can't be beat in my book.

Where the 'fall down' is it's all cast, no shooting and at about 60-70 foot you'd better be using at least a 14 foot rod. The lines may be listed as a 7, 8, what-ever, but as you add length that first 30' of line rating starts to add up very fast and can easily over load a lighter spey rod.