I play the match the hatch game quite a bit on my local tailwater. BWO patterns usually rule throughout the winter, but there are some different mayfly and stonefly hatches. But I just go attractor more times than I care to admit.
After a good rain, I use this fly for dead drift nymphing in conjunction with different stonefly, caddis, or mayfly nymphs.
When I swing for trout, it is hard to beat this fly.