I received my 6i T350 / 7-PW T250 and have two full rounds on them. As a previous T200 owner, here are some thoughts after a couple of rounds.
T250 definitely feel better than T200s.
T250 offer slightly more forgiveness on off-center hits.
Distance is the same as the previous model, no change for me. I am seeing a slightly flatter trajectory.
The biggest change for me is swingweight. I play +1/2" and with the T200, it seemed the best Titleist could do was D4-D6. They always felt a little heavy. I ordered the T250 at +1/2" and they came right at D2-D3.
Just my 2 cents. YMMV.
LB