I've worn the Stingray shoes for years, and as much as I love them they do tend to wear out pretty quickly (around 18 months is how often I usually have had to replace them over the last 15 years).  I have to say the Ninja version is as comfortable as the original Stingray, but feels a bit more robust without being too much heavier.  I haven't had a chance to see how long they last yet (bought my first two pair a few months ago, one black and one white), but I love how they feel in the gym once they are broken in a bit (they felt a little stiff for calf raises at first), and they have always felt awesome for doing footwork in the car (I drive a 6-speed manual), easy to feel the rev-matched downshifting even if I'm not threshold braking yet the shoes are not too soft for when you have to step on it harder.

Over the years I've tried other Otomix shoes for different levels of foot protection, but I think these Ninjas are a nice balance if you want something thicker than the Stingray but not so beefy as a Power trainer.