I’ve got to ask after reading your post: have you actually read these pages?
Have you actually read a review (from someone who has spent a day or two) on a Ninja 250 or 500?
I’m not trying to sound insulting, but you aren’t asking “what bike should I buy” you are asking for validation of your choice to go against the suggestions that you chose something more appropriate for your skill level.
Your comments about being mature and handling fast cars is immaterial to the risk of a fast bike. The issue isn’t that you’ll drive super fast and run into a tree. The issue is that a track oriented bike, like the Gixxer, requires a very subtle control because it does EXACTLY what you tell it to. You have dirt background, and that is good. That means you’ll have clutch and gas control. But there are still a lot of physical skills and reaction you need to train into your muscle memory before you get on a track-oriented bike (ANY and ALL of the japanese 600cc bikes are intended first and foremost for the TRACK. Anyone who tells you differently has not compared their ergonomics to a proper street-sport bike).
These bikes are not forgiving. If you make a mistake, you must have the skills to correct it. Those skills are grown by making that mistake on a bike that is forgiving enough to allow you some leaway when you mess up.
There are street oriented sport bikes out there which are both more comfortable and more forgiving of the learning process without being dull. The Suzuki SV650, Kawasaki Ninja 650, and Ducatti Monster 600/620/695. None of these are bikes that people “out-grow”.
It isn’t often you are going to hear this from me, but the salesman trying to sell you the 650 gixxer was right.
The 650 is a street oriented sport like the ninja 650. Don’t let the “street oriented” bit fool you. It isn’t a full on hard core track bike like the 600 or 750. But it looks the part, and it’ll keep up with 600s on the streets unless your buddies are riding hella-illegal. The reason the seating seems funny is because it is a mostly-upright seating position. This will be _way_ more comfortable for any length of time than the full crouch of a supersport.
My first bike was a 1984 Honda VF500F interceptor. Don’t let the 500cc fool you, it made 70hp and did zero to sixty in under 4 seconds. Its performance would put it right there with the Gixxer 650 and the Ninja 650 today. With a 12500 rpm read line, and torquey V4 motor, it was a rocket. The seating position on it was half-way between a full upright ride (like a Bandit) and a crouched modern supersport. It was hard on the wrists unless I was doing 80kph (50mph).
About the Buell. Buells are love ’em or hate ’em bikes. On of my friends has a Blast, and her husband, after riding hers, went out and bought a blast. After two years he upgraded to one of the 900cc Buells. He still has the Blast because some days he prefers riding it to the bigger Buell (can’t remember what he bought, I think it was a lightning).
Please take a moment to read these links (yes, I know it is on a Ninja 250 site, but read them anyways):
Pretty much every one of your comments it covered in them.
So to answer your questions:
No, I don’t think you can _safely_ learn on a xb9sx. It was designed for people who already had their life-saving skills ingrained. I feel it would be a better bike than a 600cc sport bike though.
Of the bikes the gixxer 650 gets my approval. As does a ninja 650 and an sv 650 (which gives you the torque of a V-twin, and is plenty fast, they are very popular with the track racers around here).
I would however remind you of the new Ninja 250 and the Ninja 500. The 250 in particular is not a bike that will give you great gobs of excitment if you ride “point and shoot”. Slow into the corners and accelerate like hell down the straights. But it will teach you (and allow you) to maintain high speed through the corners. More speed than the 600 point-and-shoot guys will be able to handle if the posting on pashnit and other forums is accurate.
Just so biases are in the open, I bought the Vf500f as my first bike last year. It spent most of its time in the shop. I have since bought a 2003 ZZR250 (Canadian spec ninja 250). I have yet to ride it, so I can’t speak about how fast it is from personal experience. Interestingly enough, I work with a lot of Harley riders and a Ninja 900 owner. All are impressed with my ZZR250 and comment that it is an awesome bike.