I have often used many plateform at the same time for benchmark performance, feature, reliability of each.
For QChart, their graphic engine is very nice et like many thing that you can find inside it, their zoom is very funny to use, it is easy to read a lot of graphics in few space. Also their software seem to have few bugs, it is robust. Big historic data, API is enought available, no limit on symbol are other important features. The problem is that if you want daytrade on short timeframe, only one thing to say: «don't trust them in fast market or at the opening». Also, the T&S are not so completed than eSignal, it lag often at the more critical moment.
For eSignal, they have feature that could interested daytrader, because you can control the spacing between candle (squeeze control), very fast refresh between switch of stock on graphic, can hide the window title bar for space saving and a lot of thing as this. Also the next release for July, will have a lot of intresting features as backtesting, script formula on tick chart, integrated trading for many new brokers and some other stuff. the most important point for short timeframe is that they are very reliable in all time. Since over 1 year, only one day, and the problem wasn't form them but from ISP with their barebone. The problem is the limit on the symbol and few access at their API if you want to program some news features.