I have not. To be fair, other than the X1 Carbon, I haven't tried any of the latest PC trackpads (Surface, Dell, etc.) in a while. Hopefully they have improved.
Dell's prove just as good as the carbons aside from keyboard. The dell keyboard is miniscule.
The x1 has what feels like a full sized keyboard in a lightweight package, lightweight like a macbook air but with a nice mechanical keyboard. The dell feels like a netbook that found some big boy pants. It's keyboard is atrocious/typing feels cramped.