The original Ninja was truly revolutionary, being the first ever 'slip lasted' rock shoe. It's hard to put this into perspective given the plethora of choice we have these days, but it really was ground breaking. As such, the Ninja was the go-to shoe for many of that era's greatest climbers: Jackie Goddoffe, Jerry Moffatt, and John Bachar.
The Ninja is undoubtedly a specialist bouldering and indoor/competition shoe, but in those environments it's a highly fun shoe to climb in, being simultaneously comfortable, technical and sensitive. If you're looking for something that fits those criteria then the Ninja will take you everywhere from circuits to projects.