I've used Orvis Mirage and have been happy with it and have some Rio that seems to work just fine as well.
I experimented with using fluro spinning line (Berkly Vanish to be exact) as leaders when bluegill and smallmouth fishing and was not happy with that at all. I found it to be much stiffer than the Orvis or Rio and tended to fail especially when throwing clousers and heavier weighted flys when smallmouth fishing.
" If a man is truly blessed, he returns home from fishing to the best catch of his life." Christopher Armour