Are the 250i a game changer in the TWS earbuds space? No. Do they have every bell and whistle? No. Do they sound fantastic? YES!!
These do have an excellent sound at the cost you are paying. Engaging low end, good midrange and a sparkly high end. The treble can get a bit harsh at times but not anything I thought to be too much. I believe earbuds should be engaging and have sound that will have you up and moving around. You know, that tap your feet, rinse and repeat type sound.
The battery life is mediocre. The wireless range is decent. Voice quality is also decent. The comfort will really depend on the user. I find these to fit fine in my ears (bigger ears here). Not sure on smaller size ears. Fit is hard to judge for others.
These are BT 5.0. No ANC or any fancy codecs. I'm ok with that simply because of how good they sound. KOSS typically doesn't disappoint me in their sound quality. These are no different. I probably could or should knock off a star for the short uptime on the battery, but, I've used them in short sessions and was fine. They'll last a workout, run/jog and partial work days for most.
Enjoy the musicality of the 250i!