Yes @ikh, Xamarin Studio was built on top of MOnoDevelop and the same developers worked on both. Right now Xamarin Studio is way better than the old MonoDevelop and is still free to use. It has the same abilities and functionalities MonoDevelop had but it has additional features (comercial though) that you may acquire if you want. You will be able to use Free and Paid Components from Xamarin store even though you are not required to acquire the commercial licenses to use it.
Open Source or Free Features:
- MonoMac
- GTKSharp
- All Mono libraries
- XSP/ASP.NET support
- Other language support (boo, F#, etc)
- Free components from Xamarin Store
Commercial Features:
- Xamarin.Android
- Xamarin.iOS
- Xamarin.Mac
- Commerical components from Xamarin Store