I use alphatrade, which I love. Lots of people provide L2s, but if you're a tape watcher, which I am, the alphatrade screen is really well set up to give you hints and clues...if that's your thing.
Some people don't care, and a little 1"x1" box will do for them, but I get alot of my clues from the screen, so I go for the best one I can find
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If you take anything I say as advice, you're crazier than I am.