Ken, if you are daytrading stocks using TWS, then there are a good few important chart features missing, depending on your strategy.
E.g - say you are going to daytrade using 2DHLB - 2 Day High Low Breakouts - then it is very handy to have a simple "indicator" that will add the PDH and PDL to your charts automatically, to save you dragging horizontal lines all over the place.
This is a real pain if you have 20 to 30 stocks that you follow!
I have requested this simple feature from IB, for a good few years now, but they never listen - this is only 1 aspect of their customer service that sucks.
However, other than this very important feature - ability to auto add horizontal lines for OHLC and Previous Day OHLC, the rest of the charting is OK - not brilliant, but Ok.
A very good free programme (limited functionality) that links to IB data feed via TWS or API Gateway, is MedvedTrader ( updated Quotetracker). Quotetracker was better, bust just my opinion. Paid fee adds more functionality.
Overall, hard to beat IB, but their basic charting sucks, and they have no intention of doing anything about it.
Depending on how you trade, this can be a major issue, or not relevant.
IB's big advantage, especially for daytrading the e-minis, is the TWS booktrader with customizable buttons for fast order entry - hard to beat it, and so far it is the best one I have come across.
J_S