I haven't used IntelliJIDEA, but I do use Jetbrains' Resharper, which transforms VS into a much better IDE. If that's anything to go by, IntelliJIDEA's intellisense will be better than VS's intellisense.
Having said that, I just watched the screencast[1] of Python intellisense in VS, very impressive.
Sorry, not trying to bust on you, but I write in all these IDEs...I still love VS.
But hey, C# is just a copy of Java, so maybe it evens out.