Forty years ago, he said, you only had Yamaha and Honda in the 125cc sports bike market; now there’s Yamaha, Honda and KTM. The Aprilia RS4 125 is an Italian designed track orientated bike with racing pedigree, but how does it compare to the competition in terms of on road and track performance? There is often riders debate as to which bike handles the best, which bike accelerates best and which bike has the top speed. It's claimed some like the Aprilia for its edge in corners, others say Japanese alternatives are more reliable and deliver smoother power. So without further ado, let’s see what real world riders have done with these bikes and how the RS4 125 fares in comparison.