I want to switch over to Mono from .Net (plus Visual Studio to whatever IDE in Mono).Is this going to be really tough?
What are the issues I would face?
Than
I believe Mono hasn't quite caught up with all the .Net 3.5 libraries and hence has either no or partial implementations of them. Mono will always lag a bit behind Microsoft, but it's a fantastic achievement and a brilliant piece of work.
have a look at the Mono Roadmap