Sandy is a good creek. All the smaller tribs there can have good days and bad days, because of the flow and migrations of course.
One thing to always remember about Sandy though, is its watercourse without a dam to stop fish is much longer than most streams up there. Soooo, you can fish a section and have a bad day, while someone a mile from you caught 30. And i mean that literally. We spend quite a bit of time in LO tribs in fall, and it just takes time to learn all the areas, and the likeliest spots on a given day/conditions. I could write a novel on this post, but i wont bore everyone lol. But I wouldnt give up on that steam by any means. Starting about mid November, its a great place to be. Walk and look.
Im not sure why its better than other streams for browns, but it does seem to be. In what I thought were the best years up there, 2010 to about 2015, we caught many, many browns there and the size on some fish was outrageous. My Dad and I had a few days where we each landed multiple browns over 30", and there was a few we got up to 16 lb. I primarily spin fish but when i flyfish there think eggs.