Wii Warm Up: WiiWare and VC vs. XBLA vs. PSN

Now that Nintendo's WiiWare channel has been out for a decent amount of time, how do you feel Nintendo's game-offering services stack up against those of its competitors? Obviously, XBLA has the most games, but which service offers the best quality games? The fairest prices? The best interface? What do you see as a strength or weakness of Nintendo's services when comparing WiiWare and the Virtual Console to XBLA and PSN?