I don’t know, did you try to customize both? I did and I can tell you there is a massive difference. Have a look at the source code of both if you’d like. Material UI is like a full framework with a ton of specific tooling around it. Chakra is more like a library based on “standard” tools of the ecosystem, and it has a much smaller footprint. Worst case scenario I can just copy the code from chakra to heavily modify it. Don’t try that with material, it will be painful.