Lap record belongs to a MotoGP 250 2 stroke, the 600 has 1 tenth of a second faster time than liter.
When you ride with the 600's the liter blow them on the straight, downhill, through maximus the rest the 600's are faster (IF and that is IF in very good hands). So for an extremely good rider on a 600 they will barely beat a liter, for the mere mortals the liter beats the 600's easy. This "well correct me if I am wrong NOAY" is due to very few riders are that fast in the curves unless they're pro's so the 600 has nothing on the liter, as the fast sections the liter leaves them in the dirt.
Bakerboy who is a very fast rider in curves, had his VFR800 scraping the fairing (it's true) exhaust and stand last time on Bira, but had no chance of keeping up on the straight, summary he and Frank kept the same speed. Frank did his 2nd day on the track with his liter...
A liter just makes it way easier to keep good lap times, even for amateurs. At the end of the straight my bike did 278 km/h before I hit the brakes, the 600 track bikes can barely reach 200 on the same stretch. Hence you have to be extremely fast in the curves to keep up with liter time. I know I am definitely not that good, very few is and the few race pro.
From being a 600 convert I admit the liter is easier to ride, I would not go back to a 600 again. Not because I just bought a literbike, but because that massive power and grunt makes the bikes much more relaxed, easy and fun to ride. No buzzy gear gear gear, just twist and it grunts and goes.
I loved 600's light and I felt fast, however going liter I have to say the torque alone makes them worth it. In lax speed 90 km/h in 6th gear, I twist and it kicks like mad and goes, try that on a 600 supersport, no way you can do it. You have to stay on top of the rpm all the time feed, rpm gear, always stay on top of the powercurve. Nah I'm older and lazier liter makes it easy...
The price difference even in US is like 30 - 50k baht so what's the point with a 600 supersport unless you are racing that series? The few who do in Thailand are pro's so you'll never reach the level unless you're something we all are not anymore "young" and have time and loads of money to get good enough. Liter is filled with happy amateurs, you can race and within reasonable time and money invested be on the ball with the rest in your class.
Not telling anyone what to buy, but I had the same idea before, go 600 and so on, well I did the unmanly thing and listened to NOAY and other people I know and respect's advice. I went liter and now I understand why they told me so.