In terms of "accuracy", and having to play a hard-core frag-fest, the mouse easily wins (nothing comes close, as you need perfect, fast control).
But in terms of "fun", and what I would be most likely to play these days - Wiimote only. I gave up on mouse controlled shooters a long time ago, and gave up on control-pad shooters not long after that.
Still waiting for a Wiimote shooter that sucks me back into playing FPS's.
Gesta Non Verba
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