Well, _I've_ played it....
One thing to remember is that, like the monk, you aren't really a tank. In general, an equal-level fighter will probably dish out more damage than you in a stand-up fight, and they can probably last longer too. This is for the following reasons:
- lack of armour means low AC, at least at low levels
- like the monk, you're more dependent than most other classes on good stats: Dex and Wis for AC, Str and Con for toughness.
You have the advantage of mobility, especially with feats that boost your speed, and general flexibility. Because you're not as dependent on heavy armour, you're not as troubled by attacks that bypass it (touch attacks, area-effect spells, etc). With the right feats, you can also up your buttkicking potential to levels comparable with the tanks -- if that's what you want to do. With other feats, you can be almost as untouchable as the monk.
Note that the class has the potential to be the basis for lots of different character types, not just kung-fu monks or ninja. For example, you could make a classic rapier-wielding swashbuckler with it. Or swap out the Wis bonus to AC for light armour proficiency, and you have a functional "light fighter", who's not as brawny as the classic tank but can kick butt just as well. Or change around the skill list to put more emphasis on outdoor skills, and take the Track feat, and you have a workable alt.ranger. Etcetera.
I've also contacted RangerWickett about submitting the whole shebang (base class, feats, PrCs and styles) to the next issue of Asgard. If anyone has any suggestions on what they'd like to see in the article, feel free to tell me.