IB data feed. There is an option in Sierra charts to download every 5 seconds a very accurate bar, and I have this set. Without this, the spikes sometimes cause the highs and lows to be off by a few ticks, but with this option, the data is damn well accurate.
I have also paid for the data from Sierra Charts which is very good, but I just don't need it, so after a few months of testing, I went back to IB. At the end of hte day, I always reload the data to get the very accurate data from Sierra Data Feed, and hardly anything changes.
The only drawback of IB data is the Bid/Ask volume is not accurate, so you can't use studies like cumulative delta or tick based charts.
Thanks for the detailed note.
Well, if you use Sierra Chart platform with IB's data feed, did you notice any issue with TSLA chart such as chart not being displayed or taking too long to display in last 2-3 days?