Update: I completed 30 days of DAS trader Pro, using the Sim Account. I will not be continuing with DAS. Their lack of customer support, and poor attitude during my correspondence with them is a deal-breaker for me.
Live, side-by-side Level 2 comparisons show DAS and TOS to be perceivably equal in speed and response. DAS has "more prices" but many of them are duplicates - so it has more visual info to interpret, to get the same result.
Some of my fills in DAS Sim were erroneous... fills that showed up many percentage points above the top wick of the candle... how can that even happen?
In Sim, you can short even if the broker has none to short, because DAS does not process through the broker... so this is not an accurate Simulator Experience. It also does not calculate fees and commissions, so you have no facts to compare.
TOS has better charting than DAS. I know multiple BBT members confirm this... some do not even use DAS charts at all, because they don't compare to TOS's.
If you use Interactive brokers, you are required to use the "SMART" routing where they decide the best route. This is similar to TD Ameritrade's "Advanced Routing Technology" https://www.tdameritrade.com/tools-and-platforms/order-execution.page So you are leaving it up to the broker to select routing in either case.
I found execution speed to be within the same second as the order placement in both TOS and DAS... when comparing timestamps. (Of course DAS was in SIM... TOS was real live trading).
I have an easy TOS workaround to DAS's "sell half" hotkeys/buttons ... open a second "Active Trader" window and set your quantity appropriately. I am not using the "Andrew Aziz/Ross Cameron" style of trading, where you move quickly into and out of trades repeatedly, so this workaround is more than adequate for me.
I'll stick with TOS for the time being, and investigate IB's TWS platform. Successful traders such as Michael Goode have found TWS to be their platform of choice.
I hope this helps anyone looking to learn more about the differences between DAS and TOS... I'm happy to answer anyone's questions!