Bottom Line upfront: I would stick to TradeStation.
I Currently have TD and TradeStation. My original plan was to go with NinjaTrader with a multi broker license, utilizing TD for stocks and one of NT brokers for futures.
However, I really like TradeStation now that I have it set up. Their commissions are on par with NT brokers for futures and they have 0 commission on stocks.
I still like the looks of NT interface, but, it cost significantly more upfront and has higher monthly operating costs to do what I’m doing with TS.
From 2008 to now: I went TD Waterhouse -> Fidelity -> TDAmeritrade -> USAA brokerage account (super expensive compared to others) -> TS
As for tick speed and order placement, I can say TS seems much faster than TD, especially in futures. I was getting owned trying to trade futures in TD, with tight stops.
I remember the trade that made me stop using TD last year. I placed a trade in CL with a 5 tick stop, and I got stopped out, even before my trade showed that it executed. After that, I started transferring money back to my checking account. This was costly as I was transferring shares and money.
I then started investigating other brokers, in the mean time I put my money in a USAA brokerage and was day trading there. It was expensive compared to TD, but I wasn’t going back to TD. TS was running a zero commission promotion for military and first responders, being prior military I jumped on that. I transferred in 40K to start trading their software. Now that I’m comfortable with TS, I’ve transferred my entire portfolio to them.
TS Software: I really like it now that I have customized it to me. It actually took a long time to figure it out and how to best utilize it. I now have my radar setup the way I like it, to include predefined alerts. I have not automated my trading, but I believe TS would allow that.