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.
I can't say how it compares to other brands but I've been using a selection of the latest Boreal models during the last year or so and the Ninjas have emerged as a clear favourite for me for everyday use. The only thing they seem to share in common with the original Ninja is the fact that there's no laces or velcro, as the heel stays on magnificently well while heelhooking and they're very precise on small edges and toe pockets.
Not sure it's a good idea to rely on my ideas of sizing. I'm a 7.5/8 street shoe and my Ninjas are 6.5, which is about as small as I'd comfortably be able to squeeze into. Another half size bigger would still climb pretty well for me.
That's really interesting given I'm also 7.5 - 8 street shoe. So to clarify 6.5 for very snug, 7 still pretty good but not as crippling? (Don't worry, I wouldn't buy without trying, but if I need to order a couple of pairs online and then return one this has been really helpful, thanks.)
I've been wearing mine for several months now, for anything beyond warm-up level. While quite painfully tight at first, they soon became wonderfully snug, but haven't stretched any further in the ensuing months, so they still feel like top performance shoes even though I've had loads of wear out of them. I'd certainly be keen to replace them with the same again when they finally wear out.
I'm a street size 7.5 ish. I got 6.5 Ninjas, tried them out at home, bottled it on size so swapped them for a 7. I can now wear them for 40 - 45 minutes easily, but they are still snug and precise, and a great complement to my other stiffer shoes.
My experience was that it was difficult to get my foot in, but once they were on they weren't painful, so there's the potential - if it is your toes that are hurting - then they could be a little on the small side.
As an update (which won't be weekly, don't worry). I used them again yesterday, switching between them and my knackered lace-ups and the ninjas felt much much better by the end of the session compared to the one a few days earlier.
No unbearable toe pain, still very snug, but they really seemed to be softening up where I needed them to without losing the feeling of precision.