So having both IB and TD and having started with and used DAS heres my two cents, as well as my current dilemma.
DAS is a superior product and experience for daytrading when you utilize quick executions and need in and out of a trade. Its fairly simplistic user interface but sometimes thats a good thing. So i recommend first trying to understand how you think you'll trade, then try DAS for the 3 month trial to understand and learn the platform. I recommend learning with the platform you think best suits the style you intend to pursue.
TD with their TOS has been what i've held and use for swing trading. Its much more intricate and nuanced with too many features. The biggest problem is the lack of ability through TOS to trade quick in and out scalps and get filled. Now you can link DAS to TD, but the last reviews I saw and consensus was the filled order was still lagging compared to IB.
The issue with DAS is the cost. Now we are in post covid world, my ability to scalp / day trade more than one two days a week has diminished and I find myself not able to utilize DAS to justify the cost when I can use TOS/TD and IB directly to execute my trades either swing, or slower plotted entry and exit day trades.
So now I will likely take IBs TWS for a test drive and see if that fills the need for a little better balance.