I have a 60" mid mount mower on my t233. I am not impressed with it, but I think part of that was my situation. The deck was bad at scalping, which was partly due to the width, and partly the small roller attached. The biggest problem with cut was the mower just didnt seem to chop the grass up at all before it would periodically discharge clumps that werent mulched. Maybe I should have tried some aftermarket blades. Due to the small size of the fenced in paddocks on our property, I found that my cub cadet 54" riding mower could do a faster job. Also had to keep an eye on the FEL that I didnt hit somthing. On a large flat field it would have probably done better, but I bushog those areas.
I feel like the deck wheels were a poor design, you will see used examples with the vertical wheel shafts bent or broken, especially where the shaft is cross drilled to allow the wheels to turn at 90 degrees to remove the deck. That cross drilling created a weak spot with very little metal that is easy to damage. One of mine eventually broke and we had to weld it back together.
One of the plastic deck wheels also got eaten up when the pressure from the bent shaft caused the outer hub to rub away at it. The cost for a replacement wheel or shaft from the dealer was outrageous.
The deck lift had very little actual lift in it, due to the small clearance between deck and tractor. It was difficult for me to remove and attach the deck when I wanted it removed so I could do other tractor related things that the deck would frequently get hung up on. I would recommend to get a rear 3 point hitch mounted finish mower if you ever think you will need to frequently remove a mid mount for clearance during other tasks.
On the plus side, the deck itself is very heavy duty and fabricated. Had the wheels and their shafts been a better design I might have felt differently about the whole thing.
I say these comments to give you my opinion and experience. Had the layout of my property been different I may have put the mid mount mower to more use. (I also dont know if the one for the 353 is of a substantially different design). So your mileage will vary. I occassionally see used TYM mid mower decks on craigslist, so you should keep an eye out there. Ive thought of grabbing one for a spare, but in the end I doubt I will mount mine again unless the cub cadet breaks down.