Desmos has a far smoother UI. Geogebra will often convert equations into its own format after clicking away from the equation editor, and if you mistyped or want to change the structure you must erase and re-type the whole thing—for example, typing f(x) will convert the equation into its own format where you can't edit parameters or the function name. Desmos leaves your input as text, allowing you to change input at the character level. From my high school experience where both were used frequently, a lot of frustration was expressed with Geogebra where missing a parenthesis forced you to re-type the entire equation since it often assumed the bulk of your equation was a parameter, and there was no way to correct it.

I haven't heard of GeoGebra before! Really cool. Thanks for pointing that out.