Its a good bike, but its harsh price tag put it out of reach of most of my 17 y/o biker friends - I saved up and bought one that was just under 3 years old with 5k miles for 2 grand. Probably the biggest mistake of my life so far.
There are *ZERO* aftermarket parts for this bike, and even the manufacturer parts are hard to come by - It took me 3 weeks to replace my sprockets, and even then I couldnt even attempt to fiddle with the gear ratios because the only ones that were available were stock size.
My side stand sensor broke, so I set off with it down and subsequently crashed at ~15mph, causing about 400 pounds worth of damage to the expensive (and very hard to come by) fairings. The fuel light indicator comes on when you have about 30seconds left to live, pretty much useless when you're heading up the A5. The fuses will blow, out of nowhere, I even had a professional electrician strip it down and rebuild it, he couldnt source the problem. And after 100 miles on this thing, death seems like an easy way out - then again, it is a sportsbike.
On the bright side, its absolutely gorgeous, a real head turner. I went so far as to give it a custom paint job (black/green) and its got me plenty of attention form the ladies.. the perfect wingman. Its FAST, not just for a 4T, but for any 125 machine - it'll redline at 74, but keep going on till 85mph when you finally decide that you're 'overdoing' it. Short distances down the shops etc are a thing of beauty, handling like a dream.
But the real shock comes in when you put it on a race track, it corners like you wouldnt believe, infact I think I managed to get my knee to about 3 inches off the ground, before I bricked it and slowed up. The acceleration is good, but not great, if you put it next to a destricted 50cc machine, you wont see much difference up to 30mph - but once you hit 4th gear, it'll just fly.
I managed to safely clip on a 16tooth front sprocket from another bike (stock is 14) and it put the acceleration down a decent amount, it'll now do 0-60 in around 16 seconds. But the top end has shot up to a whopping 94mph going down a steady hill.
Overall, a good bike if you have the money and time to look after it properly, I'd choose this over a similar prices RS anyday.