I'm comparing IB (TWS) to QCharts: The quotes don't even match...for example, IB shows the best ask at 15.82 (28) while QCharts shows the best ask 15.83 (1).... Is IB showing me something that isn't on Level II or is QCharts total crap?
I think QCharts excludes ecn's from lev II for now. Seems like they have some statement or something on their site about it. I don't use them for stocks so can't say for sure.