[crisedward]

so, if it's for normal development it should be fine, but if need to use libraries, plugins and stuff for a more deep app I should learn objective-c?

[yamalight]

well, for normal dev you would also need to know the basic iOS SDK classes, structure and their usage. the main advantage is all the c# features and c# syntax (i personally don't like objc at all) you can use in iOS dev with monotouch.