I'll chip in on the side of the NS, had mine for about a year now since my full suss was stolen and loving it! Bags of fun, all day comfort and great for hooning around on.
I'm 5"10 and have the large (bought it cheap off a mate as I just needed something to ride) but it's too big to be honest, the TT is pretty long.
My missus has an 18" inbred and I much prefer the Society, never ridden a 456 though. Either bike sounds like it'll be ace, personally I'd get the NS cos every man and his niche dog has got an on one these days ;)