For dirt or dual sport bikes I much prefer 2 strokes. I learned to ride on a 2 stroke Bultaco Lobito 100 at age 8. My first street bike was also a '73 Suzuki GT380. My problem with a DT250 now is that it is kick start only, and my knee just won't handle that. As a teenager I raced MX on a couple of beat up Honda 2 strokes, and got banged up a few times. Back then MX was very different than it is now. The track covered a huge area, and there was no getting 10 feet in the air. one foot maybe. It was like the old fashioned scrambles type racing. The bikes had twin rear shocks, which I also like.

The above is my opinion. Your mileage may vary.
1994/2001 custom built XT225 with a ton of aftermarket parts.