system
A chat on subreddit /r/wallstreetbets
human
Is there a place where I can find comparisons of different brokerages?  I tend to make less-frequent, larger trades.

gpt
I got 8 cents per share price improvement on Schwab for my Rockwell sell yesterday. I only sold 4 shares but if you are a big money player it would be worth it. I can't use RH because of broker restrictions from the firm I work for (investment management industry). 
 From what I've heard Fidelity is the best on price improvement. td ameritrade is also good but they have higher fees, at least on options. Schwab is right in the mix too.