This will most likely be closed since the choice is based on the preferences / opinions you have.
Some points I noted using both of them / searching about this topic :
- XAML is in theory more powerful (since it is based on native elements), in practice the difference will be invisible.
- Technically there is no limiting choice, everything that is possible with one is possible with the other.
- The community is larger for Blazor since the framework is not specific to MAUI, so it is easier to find documentation and help.
- Blazor takes advantage of all the JavaScript libraries developed for the web.
- The XAML components are converted into native elements and the design will be the one of the platform (loading, dropdown, ...). The UI will be more intuitive for users.
- In some cases debugging with Blazor is complicated.
- Blazor make it easy if you want to create a web app from your application
The rest is totally opinion based : for me it is easier to create Blazor components than XAML, UI definition, styling and Binding are much less verbose with Blazor. Blazor seems more mature and better built than what XAML offers (as of now).
It also depend if you are working in a company or doing it as a personnal project. Most companies will try to stick to the same techs for convenience sake, so if you are already working with WPF go with XAML, if you are working with Asp .NET go with Blazor.