The LAS is for very "Low Air Speed" airplanes, most typically the LSA's that have stalls down in the 30's somewhere. Think LAS is for LSA! Go with the standard one and you'll be in good shape.
Stein is correct. There is no difference in the two units except for the integrated low airspeed warning. The regular version is adjustable down to ~70kts. The LAS version is adjustable down to ~50kts.
