For starters VB.NET usually needs more lines of code to achieve the same result that C#. And VB.NET is not as nice at handling certain logic operators or statements without additional checks in you code.
From my experience with VB 6 allowed lazy programming and that's why it was popular. Moving VB to .NET microsoft tried to neaten the language up but all the VB developers moaned about "but in VB 6 we just had to....." so they put all the shortcuts (usually
meaning more processing) and lazy options back into VB. I am a VB programmer and I hate the language when compared to C#, found the learning curve of VB 6 to VB.NET to be worse than VB 6 to C#.