The 1.5" travel gives greater convenience because you have to adjust the main focuser less often while the 0.8" travel focuser with it's shorter adapter consumes less backfocus. With the accessories I use behind the focuser I'm wanting to take up less backfocus to get closer to the ideal position for an EdgeHD I've recently purchased; distance from the rear cell to the eyepiece field stop (or imaging plane) is more important with the Edge scopes than the standard schmidt cassegrain, due to the coma correcting/field flattening lens in the baffle tube.
