If you look at Codas interface, you will immediately notice its more up-to-date and is just as easy to use as opposed to Notions dated and more busy interface. Knowone except for really knowbody likes bad interfaces or even poor ones:
Coda's marketing is also better aside from some of the imagery.
That image of the frog is unessesary in my opinion, but overall Coda is simpler and easier to use than Notion.
If you look at Notions interface you will see its more busy and dated looking as I should point out.
As you can immediately see, they both do the same thing. One being simpler and less dated looking. What else then? Well, the navigation for Notion is better, well until you have a bunch of docs filling up the side. Coda on the other hand has just folders on the side. So, overal as you can see, Coda is way nicer looking and better in terms of usability. So Coda wins.