I've been using Public to do earnings trades for a couple weeks (including double diagonals). Their spread trading features might still be in beta (they gave me early access when I requested it), and there have been some growing pains, but their platform seems to generally be quite stable. The word is still out on execution quality. At least once I couldn't get a fill on Public but then tried the same order on tradier and got an instant fill, but the orders were not open at the same time so it's possible timing factored in. They should be sending things to the same exchanges any low-cost broker would prioritize, so I wouldn't expect a huge difference to tradier there, but I know one thing that can make a big difference at times is which liquidity providers they sell most of their order flow to. Each broker usually has their own list of providers and priorities within the list. You can look up the data in their filings but they may still be finding their footing in that area since they are pretty new. Usually, you can tell your order was internalized with a liquidity provider when it is instafilled, vs sent to the exchange and sits open on the orderbooks. Different list of liq providers can lead to orders filling right away on some brokers and not on others, but it wont necessarily always be better on one broker vs another.