I am playing a Ninja from Complete Adventurer right now. His Ghost Step (Invisible) Ki Power is *way* useful- and a really cool game effect IMO- but it is (probably more than) balanced against the Rogue's Sneak Attack since Sudden Strike is so much more limited without taking effect due to flanking. Since he can only use his Ki Powers 4/day, I have to be much smarter about when to use it. Using Improved Feint instead on occasion is a good option to deny my foe's Dex modifier. I am really digging the class, and think it is a perfectly legitimate Rogue alternative for the right character.
