First off, I have never ridden or owned a bike at all. Just wanted to get that out of the way. My first question is how difficult is it to stand them up, I have the stupid fear of laying it down and not being able to get it back up in the middle of the road somewhere. I'm 6'3"/4" and around 165 and I really don't want to look like a dumbass, I know I'll drop it at some point so I'm trying to get a feel for what I'm getting in to before I go ask someone at a dealership.

 

You should be able to upright a 250 with no problem.

 

Welcome to KF

You may find that you will be uncomfortable on the 250 because of your height. I would sit on one and check that out. I have not sat on the newer gen ninja 250's yet and they are running the 17" wheels on them. Whereas the older gens used the 16" hoops.

They are a light bike so you shouldn't look like a "dumbass" while asking for help to pick it up. lol

 

Welcome. buy a KLX first, learn to ride both off and on the road and then move up to street bikes.

 

I would say go with the 250. It's a nice bike only 400lbs. I tested 600+ models and the 250 was fun to ride. Its more fun to ride a slow bike fast then a fast bike slow. 600+ are made for the track and it would be hard not to speed.
I would say if you want a big bike go for it but take it to the track and go as fast as you can and get it out of you. Good luck.