If I have a team (a "team" of me +2, don't think too big) of coders proficient in both C# and C++, what advantages would using Xamarin bring over having the common/cross-platform code in c++ (objective c++, ok...) and using the platform specific languages and tools for the UI and whatever else ends up being platform specific? (besides C# being a much nicer language, of course)
There are tons of sdks and libraries that you can use with C# / .net. To name just a small few that I have used: Stripe's .net sdk, parse.com's sdk, amazon's sdk for .net... the list goes on and on. Pull their dlls in and just use them. It makes a cinch of hooking into other services.