No - I've never worked with Xamarin (although I'll be looking at it in the coming days / weeks for a personal project - it looks quite sweet now). But I've got loads of experience with both .NET and Objective-C / Cocoa.

Most of my experience has been on the .NET platform and primarily on the backend / distributed systems side of things.

However, between 2010 and 2013, I was co-founder and CTO of a tech startup where our main product was a fairly sophisticated native iOS app. Being a bootstrapped startup, I had to do all the tech work myself. So I got a lot of experience with Objective-C / Cocoa that way. On the back of that, I got a contract to develop a native iPad app for the BBC, providing me with some additional experience building an app for an external client.

When I landed on the job market in January last year, I was therefore happy to take either an iOS contract or a .NET one.

I ended up taking a .NET contract. And to be completely honest, large-scale software systems / distributed systems is really where my heart lies. So I'm now pitching myself as a .NET developer only as this is the type of role I'm most keen on.

I'd actually be really happy to take on a role that uses another stack as well. But as a contractor, it's not really realistic to expect a client to pay you to learn a new language / stack :)