To jump on what ib516 is saying... I think that you will feel more "sluggish" in the F250 with the lower rear axle ratio.
You have similar horsepower between the two, but the F250 probably weights 1200-1500 lbs more than the Tundra. All things being equal, that extra 3/4's of a ton will make the Ford feel slower.
Then when you factor in the lower rear ratio, it won't feel as powerful.
The F250 will handle the weight better and be a better overall towing vehicle, but it will feel slower. I would encourage you to research and consider the 4.30 gears in the F250, which would make the truck feel more powerful under load through the lower gears.
Either way, the Tundra is probably close to, if not over, the maximum payload with an 8500 lbs trailer (assuming 13% tongue weight, or 1100 lbs tongue weight), whereas the F250 would have plenty of payload to spare. Brakes are bigger, frame is bigger, tires are likely more firm, etc.
I miss my Tundra, I really do. It was a great tow vehicle for my 6500 lbs trailer. Once I stepped up to an 8500-9000 lbs trailer it became quite clear that I needed a heavier truck. My Ram 2500 allows me to pack whatever I want and not worry about tongue weight. I think you will enjoy a 3/4 ton truck when towing those weights.
