The 250 style guitars are 17 inch size with a 25,5 inch scale length, the 150 style is a 16 1/4 inch guitar with a 24 3/4 inch scale length.
The amalgamation of the two is the 150/250 style; a 16 1/4 inch guitar (like the 150) but with 250 style features like the Y-shape tailpiece and open book inlays. If the 17 inch guitar is to big for you, the 150/250 style is an great option.
But there is more............ introduced in 2015 alongside the Collection is the prototype DS-200 guitar. This is a guitar truly in the middle of it's bigger and smaller sisters with 16 5/8 lower bout and 25 inch scale. An intermediate model with great playability and sound and it even comes with a perfect fitting vintage Lifton case if you want!