EASILY, hands down, the best darts scorer on the iPhone. The Winmau one looks better, but n01 obviously simulates an opponent for you, and considering n01 is only 59p, which one would you rather have?
Plus, I've only had it 2 or 3 weeks, and they've already updated it twice.
The only flaw with it I can see is that you can't seem to set it so you're playing your opponent for sets; you can only play for legs. I've been at 7-8 against my opponent and wondering when the hell the set ends...when I use the PC version I have it set for best of 5 legs. You don't seem to be able to set that up on the iPhone version....yet.
But just in case anyone here has an iPhone, you NEED to get n01 for it.
(Just wish I could use my handy dandy ripped-off Russ Bray sounds files on it...curses!)