yz250f or kx250f for beginner?

Hey everyone, new to this website so let me apologize in advance if this has been asked on here, But I have been looking at some newer model Kx250f's and Yz250f's to buy to get into some track riding, I have rode the track a few times on a 2003 Kx250(2 stroke) and 2011 Kx450f which is my friends bikes. I rode at Threepalms and Rio Bravo here in the Houston/Conroe area. I did fine on both bikes and Was able to clear a good amount of the jumps and ride smoothly through the corners, But I feel like a 250f would be perfect for me till I get decently better and more flow on the track. So my question is which bike would be better for me, Im looking at models at least 2014-2018. I have read a bit on both but would like other riders opinion, Which will feel lighter on the track and have better power throughout the low revs - mid range- and high. I would be keeping regular maintenance on the bike of course but which is more reliable ? and has better cornering ? Any reply would help, thanks in advance. Just wanting a good bike to get good on the track with.