What's good fluorocarbon for a spinning and baitcasting reel?
I like Seaguar, and Pline.
I only use fluoro for leaders and for that I use either PLine CFX or Sunline FC Sniper. Spooling straight fluoro on a spinning reel isn't a great idea unless it's a low lb test (like 8lb or lower) because it tends to be stiff and a pain in the a$$ to deal with. Should be okay on a casting reel though.
Seaguar AbrazX is my favorite!
Seaguar Invisx. It's more limp than abrazx, which greatly helps in reducing line twists.