I used to have a CBR250RR as my learner bike. I loved it. Loud noisy but it's not until you've owned it for 2 months that you realize it's fkn slow. And makes too much noise for the speed you're actually going.

For a learning bike you are really only looking for one thing. RESALE. Buy a bike others want. I bought mine (black) for $5500 I think. When I sold it 6 months later, TeamMoto came to my place without a few hours of it being up on bikesales for $5900. Obviously they snap up all the good condition (specially black!) cbr250rr's to sell them at their premium.