Just speaking from personal experience, I started riding two years ago after taking the rider safety safety course. I had the ultimatum of which size bike I wanted to get for my first bike. I was between the 250, 650, or zx6r. Against some recommendations of some users from this forum, I ended up getting the zx6r and looking back two years now, it was definitely the best decision I could have made. The bike still suits me perfectly fine and I haven't outgrown it (although I wish I could upgrade to a zx10...someday ha). If I would have went smaller, I would have definitely regretted doing so and probably would have sold it within months to upgrade. Just my experience though, as I'm sure everyone else is different.