I have used QT for a few years - I like it a lot. But it has recently developed an unfixable bug that has reduced my use of it to monitoring indexes. So I have looked at a few alternatives including NinjaTrader, SierraCharts, Multicharts and ProphetX. I have pretty much decided on ProphetX. It's not quite as versatile as QT (as a chart program - but much more so in other ways), but it is as intuitive to use, faster to change settings and in its response, and has a couple of features I really like. It also includes DTN's dedicated data feed (equivalent to IQFeed but seperate servers I was told). It doesn't have an IB connected trading platform, but I use ButtonTrader anyway. If my QT bug ever does disappear with a subsequent program update the combination of it with ProphetX will be a good fit for me.
Ninja is free for charting, and might be a good first step before moving to Ensign or Sierra. I am using Ensign, for their Pyrapoint Gann analysis and Presavento addon, but I may try Sierra in the future for Open e cry and IB. Ensign has had some rough spots working with the Ib and DTN historic feeds. Of course if DTN does not have the data and IB only has 5 days worth the daily charts aren't really very helpful
It's not too bad, maximum update speed is once per second. What i like is ChartTrader (part of TWS charts), I'm trying to configure it to also accept complex orders. It's nice to drag your order through the chart updating it immediately.