It's funny asking this forum about dirt bikes because if you go to Thumpertalk or any other dirt bike forum, it seems like people don't care about their bikes at all compared to the way we care about our skis. No attention to detail whatsoever, just f'in run er deep bud! More junky looking, the faster it is. Might be another reason to drop almost 7k on a new one because every yz125 on craigslist says it has a fresh rebuild, brand new this and that... Yeah I can only imagine. I just bought a 2001 yz125 last year with those claims for 1k and honestly who knows if its going to explode, run for 10 more years, who knows. All I know is that those little motors are really finicky when it comes to outdoor temp change, and what everyone is saying about lightswitch powerband, takes work to ride, etc. its definitely all true, but I never plan on racing. Just some backyard, woods, and trails and it is a TON of fun. Expect NO bottom end by the way. YZ250 has a bit more low and a LOT more mid range bark that will scare you for sure if you don't know what you're doing. You could end up on your ass in a hurry. Personally for me, 2 stroke is a no brainer because its simple to maintain and understand. No BS going on.