I guess it all boils down to what's your purpose in buying this bike? If it's for virtual penile enlargement, then a CBR250 is a bad idea. Get a 600RR or a literbike, which is a lot more impressive. Get your impressions made quickly, especially if you're a new rider - the lifespan of those bikes (and riders) can be incredibly short.
If you're a new rider, or if you just want a light bike that handles and stops well for less money, then you might be suited for the Honda or Kawa 250. Gas mileage is a plus - some of the I4 bikes get in the low thirties versus 70+ for most riders on 250s.
I'm not knocking the more powerful bikes - some of them are race bikes with turn signals. However, it wasn't what I was looking for. The margin for mistakes on the bigger bikes is razor thin, and the penalties can be severe.
As an (admittedly anecdotal) example, one of the departments I teach at responded to a double-fatality accident that occurred on a group ride. The mistake was made by a relatively new rider that had started about as large as you can - a Suzuki Hayabusa that the manufacturer claims is "the hottest sportbike on the planet". 1300cc+, ~170hp, ~600 lbs, top speed said to be ~180 mph. According to reports, he was in the middle of the group and popped the throttle and it "pinned him back" (see below). He wheelied into the bike in front of him, killing the passenger on the other bike as well as himself. It was a trivial mistake, but it cost two lives. A less frantic machine would have let him get away with that mistake and learn from it.
And no, that doesn't mean you're automatically going to die if you start out on a powerful bike. However, the additional horsepower, handling, and level of expectation from fellow riders can be a deadly combination. In addition, even if you bought new, you won't take a beating on a well-maintained 250 if and when you decide to move "up".
As always, my opinion
Luke
"pinning back" - experienced riders of high-power bikes know that you always grab a chunk of throttle from a neutral hand position - you grab the throttle with your wrist straight and roll your wrist down for more juice. Inexperienced riders often will bend their hand down (wrist up) before gripping the throttle and then roll the throttle in until the wrist is straight.
The problem occurs if you get too much throttle or the bike hooks up unexpectedly. The acceleration "pins you back" so that you can't let go of the handlebars or reposition your hands. If you rolled your wrist down, no worries - when you get thrown back you'll automatically come out of the throttle. However, if you rolled your wrist to neutral, you've got few options - either let go and fall off the back or hang on until you can overcome the (eventually weakening) acceleration and lean forward again. Flipping the bike over backwards or hitting something gets you off the throttle sooner. Yes, quick reflexes could give you the presence of mind to pull the clutch (provided you could free up a finger), but those semi-instinctive responses come from the same riding experience that would have kept you from making the first mistake.
For instance, last year on a remote and deserted paved road I drag raced my friend with his Vespa LX150 scoot on my CBR125R from a 5 mph running start. We were neck and neck through my 2nd gear on the CBR. However, as soon as I put it into 3rd - I left him behind rather dramatically. I thought he had actually eased up on the throttle - but he assured me later that he still had it pinned. And he has 25cc more displacement. My CBR125R fuel economy was also much better than what he could muster with his LX150 also (though to be fair, his LX150 is carburated). The CBR125R is much more engaging to ride, puts its power to the ground better (I believe that a manual trans still helps put power to the ground more efficiently than a CVT) and gets better fuel efficiency. They both handle very well though and are fun to ride. And the Vespa sure beats the CBR125R in terms of practical storage space.
