The reason why you guys may have a high turnover is because C# along with other skills such as ASP.NET MVC are in high demand. I get recruiters contacting me
everyday on LinkedIn about a position they are trying to fill with their clients.
C# is my primary language. If you are a complete beginner, you might want to start off with
Head First C#. If you feel you are in the middle to advance, you might want to start off with
Pro C# 5.0 and the .NET 4.5 Framework or C# 4.0 depending on which version you are using.
If you want to learn by video,
Pluralsight is the best in my opinion, but they can be a bit pricey.
Pros
I personally feel C# is light years ahead of Java. Java added features after they are introduced in C#. For example, generics came first in C#.
I have yet to find another language that exist in an echo system where everything works seamlessly like .NET.
C# and it's cousin VB.NET are used in the best IDE on the planet (Visual Studio) in my opinion.
Cons
Some people who tend to be anti-Microsoft mention how .NET (the framework that C# runs on) is not cross platform. It requires a Windows based computer. As someone who has worked in several companies over a decade (all of them Windows based environments), this means absolutely nothing to me.
Learning C# can be overwhelming at first if you have not worked in an object oriented language before. If you are already familiar with a language like Java or C++, you should be able to pick it up quickly. But you do not have to know those languages to become successful in C#.