Have had a tinker in the past, it's like ASP.net in that you are 'all in' with C# and the tooling to get things done. On the surface this seems like a good idea but these days the web/mobile scene is more separated, that is, you have client side and server side, most shops go with a SPA (single page app) type setup with a REST api, similar for mobile.
Basically, if you're a .Net shop then it's all good as long as everyone is up to date on the frameworks and technologies they bind with (in other words it's very 'enterprise-y'). If you want to keep things lean then there's things like
Tabris for mobile (javascript) and take a pick of your server side with php/node etc. Any popular web hosting service has php/MySQL as standard (and cheap), hosting .Net/SqlServer can get expensive unless you host it yourself and look after everything that goes with along with it.
What's your target area for the app's?