I have been riding for about 8 months now, an 04 plate Aprilia Rx 50. I wanted a geared bike because I would rather change gears rather than a rev & go, and having a geared bike is 'cooler' too. I only use it to go to college.
My bike is de-restricted (Has an after market exhaust installed, got it with the bike) only paid £600 for the bike but had to do a few bits to it. Easily goes 50mph, and I have had no problems with police on 40/50 mph roads. If you think about it, it's probably 'safer' to have the bike de - restricted as you can meet the speed limit if the roads are above 30mph. you won't have people trying to overtake you, beeping at you etc. In my eyes, I think its safer. Even when I did my CBT on a 50cc scooter, was totally standard and that went over 40mph, and the instructor didn't say anything about me going over '31mph'.
Out of scooters, I think the Yammaha Areox is the quickest scooter available to buy, but can't comment on reliability.