I've ridden the Ninja 400. It's a really a great bike. If I had room in my garage I would have bought the one I test rode.I understand this is an old thread but I bought a N400 November 3rd and just turned 5,400 miles this week. I love the bike, seriously and can't see selling it. However, I rode a '14 N1K last week and was hooked immediately, and I sat on a 2020 1000SX and it fits me nicely even at 5'-6", better than the 400 really. Also sat on a 2018 H2 SX and it was sweet but the 1000SX is what I want and all I can think about despite only a few payments in on the N400.
BTW, I am 55, started riding really young (5), riding a CB750 by 12 and off the street since I was 18. So I
consider myself a total newbie with 5,400 miles and 4 months and 2 weeks seat time.