"Slow" is a part of IB datafeed. It is provided "as is" at a heavily discounted price. So, naturally it has a few limitations. You need to try a few different platforms side by side to see if one is faster or slower than another. All 3 platforms I mentioned can use IB data and place trades via IB (if the user wishes). I'm glad you chose the platform to try first. If you want to read about complaints, try starting a new thread with a title like "Do you have any complaints against SierraChart?" P.S. It's software, not a broker. So, it doesn't matter if anyone else has complaints. What is important is if the software does what you need.
QT has been around for a very long time. So,it doesn't suffer from a flood of new "features" that break existing functionality. It is more of a phylosophical decision whether you prefer new features added regularly as opposed to something that works without problems. The biggest problem with QuoteTracker is it's broker interfaces will no longer be updated while brokers will keep changing their APIs from time to time. Thumbs down to Ameritrade.