Underscores are perfectly fine
I have noticed a stigma attached to underscores being used in method or variable names. For example, most people I have worked with prefer AMethodNameLikeThis() over a A_Method_Name_Like_This().
I suspect this is mostly due to tools like Resharper and Visual Studio “complaining” about underscores by default.
This default is silly, I believe. Long method names (as long as they are descriptive!) are a good thing, and underscores make them more readable. When I have the opportunity I always user underscores to make the code more readable, and thus more maintainable.
To change ReSharper’s (v10) default treatment of underscores, navigate to ReSharper -> Options -> Code Editing -> C# -> Naming Style. You will notice that each naming style has a “UnderscoresTolerant” equivalent.
Despite this, I think it is more important to stick to the team’s standards. So if the standards say “don’t use underscores”, then it’s best to stay clear.