Some people may not agree with me (which is fine) but my 2 cents on the post you quoted from the other forum. The 600cc+ veterans should definitely chime in on this one.
The post has its pros and cons. Most of which are exaggerated and blown out of proportion in my opinion.
1. Speed - Duh. A bike will be faster than a modified sports car. Physics wins. Always.
2. Brakes - No shit. This is a bike. Not a 3,500lb car. At PRS, they will teach you how to modulate brakes, both front and rear.
3. Throttle - There's truth to what he says but seriously, fuck that shit. Just take it easy when you get on the bike. Again, you will learn throttle and clutch control @ PRS. This one's a no-brainer. PRS guys - "Clutch and braaaaaake!"
4. Cost - Whatever. If you're prepared to buy a 600cc bike, you should be prepared for the insurance costs. The jump in price from a 400cc to a 600cc bike isn't that much more. Plus, you have the option of insuring through Beacon @ Cassells (I'm sure a lot of guys insure through them here.)
5. Responsiveness - Again, a no brainer. Most 600cc+ bikes have a proper suspension setup. This is a bike, for crying out loud. Handling etc. will come with experience and training/reading. Again, you'll learn this at PRS.
6. Learning - You'll likely learn on a Kawasaki Sherpa @ PRS which is I think 250cc? They're easy to learn on but when moving from that to a 600cc+ sport bike, there isn't much of a learning curve so this guy blew things out of proportion (again, in my opinion.)
7. Gear - Looks like you got that one pat down. That and you took advantage of the AYC sale. Never skimp on gear!
If you're not feeling comfortable with a 600cc bike to start, that's fine. You have other options. Like I said, Alphamale is selling his GS400. Fucking guy is riding a CBR600F4i now. It's a good beginner bike and good to learn on, a compromise between a 250cc and 600cc bike. Great if you're looking to develop your skills during your first season. Hope that helps.
Edit: As much as I love my cafe racer, I'd rock a 600cc sport bike any day.