It's not too bad, about 12-15 MB for the runtime on iOS. I'd say the main downside compared to other cross-platform frameworks is the lack of official hot reload (it's possible but really clunky) for building UIs.
Otherwise, I’ve been working with it since 2018, my app now has around 500k installs on both stores, and I’ve encountered very few issues related to the stack itself. Mobile .NET has been steadily improving, and LLMs have made the two-native-UI approach much easier: after building an iOS UI, I ask Claude to repeat it on Android for the same view model and get about 80% done instantly.
Otherwise, I’ve been working with it since 2018, my app now has around 500k installs on both stores, and I’ve encountered very few issues related to the stack itself. Mobile .NET has been steadily improving, and LLMs have made the two-native-UI approach much easier: after building an iOS UI, I ask Claude to repeat it on Android for the same view model and get about 80% done instantly.