Yeah, but those low RPMs on the SV650 get you going a lot faster than they do in 6th gear on the Ninja. On the Ninja the RPM restriction keeps you down in the 30-40mph range and rowing through gears 1-5 in wildly fast succession when accelerating after every stop. (Actually, all that gear shifting is good practice, which is another nice perk of the 250 as a beginner’s bike.)
Anyhow, Jim already posted a link to the Ninja250 wiki, which is about to become your newest best friend. Short answer: there’s a big debate about RPMs, with reasonable arguments at both extremes (follow Kawi’s instructions to the letter vs. ride it like you stole it). Personally, I opted for a middle between the two–usually keeping RPMs low (though not always as low as Kawi asked) with lots of shits in RPMs, including the occasional revs up and down the range. Because I went this route, I also opted to get my 500 mile service at 400 miles, since I wanted to change the oil earlier sooner rather than later.