Nicely done, it's great to have a side by side comparison. It's made me realize I don't actually like the fonts I was using and I ended up on Roboto Mono, Ubuntu and Fira Mono.

I'll echo what the other comments are saying - it'll be good to make it a blind tournament with some representative code samples from languages like C#, Python, TypeScript etc. At the end you could present the 'top 5' fonts that were chosen by the user (or all of them, ranked)

I'm not a fan of ligatures so I'd want to eliminate them entirely or see such things in the code sample shown so that I can choose/disallow it.

Because it's for IDEs, make good use of the screen real estate, maybe that 'about' section on the left could go on the bottom, giving the side-by-side comparison more space to view all the code.

The 'Visit Site' link could be a normal hyperlink, my browser is blocking the popup that it creates currently. All that needs to be is an <a> with a target="_blank".

Finally for mobiles I think hide that 'product hunt' badge, it's getting in the way of the buttons.