I mostly nymph where I live and this is the anchor fly to all of my nymphing situations. I tie this fly weighted in sizes 4 and 6 and unweighted in 6 and 8. I fish the weighted version as the first fly in a three-fly rig, which usually includes a bead-head type pattern as the next fly and something very small in midge territory as the bottom (third) fly. Killer rig.
I also tie them in a variety of colors - here are some examples:
This is my favorite version - The "Big Ugly" Rubberlegs:
Even Whitefish love them...:
Several years ago a few friends and I fished the Big Horn in Montana. One friend fishes only with the rubberlegs and another fly as a dropper - only problem, no stoneflies in the Big Horn and he did not catch a fish in three days because he refused to switch rigs, even though the guide instructed him otherwise.
Also, I no longer add any weight to my line when nymphing as the weighted rubberlegs is adequate to get the rig down.