The vertical ones are the old original home stereo version. They were crap hifi speakers before they were crap studio monitors.
The horizontal ones have a redesigned tweeter and crossover that made them a smoother in the upper mids. I can't imagine what the old ones sounded like if the redesign made them smoother and less aggressive.
I'm actually surprised anyone is still interested in these things. They served a purpose in a bygone era, but can be surpassed by speakers that cost less.
The only thing I really hate about them is people who don't know any better thinking that they must be the flattest, most wonderful sounding speaker simply because they were in every studio. It's the same deal with auratones, even though we are at least a generation away from newbs seeing pictures of those.
All monitors, no matter the price, sound different. There is no gold standard. There is no one that is flat and accurate throughout the freq range. (That I know of or can afford)
Some people love krk rockits. I hate em, and think they are garbage. But I've heard good mixes done on those, and shitty mixes done on high end monitors.
The point is; one needs to learn their own speakers to get the best out of them.
All you NS10 haters, go fly a kite or engage in whaterever activities you like.
Self mutilation, Self copulation or whatever tickles your fancy.
Some of the Greatest records ever were mixed on NS10s.
A lot of pros better than any of us use them still.
I love them.
Now the Ns 10 T, thats a different story. I think the "T" stands for toy.
Rant over.