You may not always get the best pricing, and also there are no market trades as of this writing on RobinHood, but the RH UI handily beats everyone else in terms of ease of use and simplicity.
The options trading functionality, for instance is very simple. You select options and then it presents you with a list of (screen) options on whether you think stock will go up, down, or sideways. Based on that, they show you low risk, high risk call options, put options or stangles and straddles. You can place a trade with a couple of taps. If you want to get more specific and sophisticated, you can choose the expiry dates and select your own call / put options.
Compare this to TD Ameritrades UI and Schwab's UI, it looks like some guys from the 90s, stuck in the 90s, are still working on the UI team.
Truly clunky, horrible, confusing and annoying.