I have both the Premier and the SL-R (standard width version of the Legacy, but one degree less stiff -- per NS). The SL-R is probably similar enough to the Legacy to give a basis for comparison.
The SL (161cm) is more agile, turns a bit more quickly, and is a bit lighter. I like it better for messing around in trees.
The Premier (163cm) is more stable and cuts through chop a bit better. I like it better for bombing down the hill at warp speed.
I'd categorize myself as a freerider who doesn't fark around in the park, and we often get wet, heavy, choppy snow here in the PNW, so if forced to choose between the two boards I'd lean towards the Premier (but it's a very close contest).
Edit: If you plan to ride the park at all, then you might prefer the Legacy.
Last edited by Toecutter; 01-03-2010 at 11:02 PM.