From my experience, if you are a manual trader, even very shortterm (seconds !), you wont notice any difference between TT and Rithmic feed.
CQG in combination with Sierra chart is also an excellent package, in the hypervolatile and fast markets of the past 2 weeks I had zero lags or problems with the CQG + Sierra combo, even in the NQ, which was jumping around like insane on those VIX spike days.
So I would say try them all out, because there are some differences, but the speed and reliability is excellent on all 3. The differences I talk about are more regarding the platforms (TT, Rithmic RTrader, Sierra Chart, CQG Qtrader...). They are all very good, but it comes down to what you really need and also just your personal taste. Me for example, I like TT very much (one of the reasons is they offer the (E)PIQ feature in their platform), but I also really like Sierra Chart in combination with CQG, it is ultra customizable. Rithmic's RTrader platform is also very nice, I just dont like that you dont have a 100% static DOM there.