I like it so far. Its more stable than command center and there havent been any LII errors since I started running it against command center. Ive never found command center reliable. Now I always know if my LII's are screwed up since I have a back-up.
I also like the fact that I can trade currency and futures although I have yet to do so. Does thinkorswim only come with a Apex account? I get all this stuff for free since Im Apex so its what I use.
Market Data 
Markets 
AI
