You got nothing to loose trying them out, on penny stocks or blocks I don't use my IB account because of cost. This coming from someone who use to make over 500 daily day trades and told by several brokers "your overloading our system, find another broker"!
I see a lot of these 'bad fill' posts on the free guys but they never post anything resembling proof hmmmmmmmmmmmmmmm
my guess, slow hand trading and data lag are 99.9% of what you think are bad fills prove otherwise, or stop posting bs
I've been with both since 1999. TDA is in most ways, better. I prefer IB for a pseudo-spreadsheet front-end. It's more transparent that switching between pages in TOS/TDA. TDA has never auto-liquidated an arb, while IBTWS liquidated a SN box of mine during the ENE blowup. IB's PortfolioAnalyst is superior to TDA's web-based EOD analysis. No question. IBTWS is better for arbs provided you don't get liquidated. To be fair it hasn't happened to me since 2001-2.
I'm not sure we're saying "free = bad fill", but that commission is usually negligible compared to fill. Brokers need to make money somewhere to maintain infrastructure, and I don't mind paying an average of $0.7 commission/trade in IB if that means my brokerage firm can provide me with a rock solid infrastructure. That said, I've traded with ToS/TDA as well, and had no issues. Their fill may be better than IB, as good, or worse. But any (i.e., your) request for some kind of proof of this is statistical ignorance, because there can't be proof that fills are better/not better between brokers, only different levels of certainty whether the null hypothesis holds. And even getting to defensible p-values that would allow for a real fill comparison would be such a pain that I rather just keep paying $0.7 commission and not worry about any of this.
Honestly I was getting better fills from Schwab than other DA on options before the Crash. Citadel internal orders were not bad. I agree DA is the best for aggressive non-market orders or pure limit orders if rebates are there.
Sure, but like you're saying, I can't use TCA to compare fills between TDA and IB. All I can do is submit the same orders to both, and then compare outcomes. But because volatility and other market conditions are going to be strong independent variables in this, it would take a ton of testing to determine if there's statistically significant differences. Gut feeling: they're all very close. Go with whoever's platform/infrastructure/services you like best.