Hi Waterop,
In my opinion, the price difference between the Agility 125cc and the Super 8 150x isn't huge and if you can afford it, go for the 150x. You get extra 25cc which means a bit more torque and hp. I know it isn't much, but I personally would have regretted if I had bought a 125cc (the 150x is already slower than I thought it would be).
Best,