I have three of them and wouldn’t trade them for the world. All have the carbon shaft and auto wind for string. One of mine has a weak spring and it uses too much line releasing it too easily. They are replacing the spring for me even after 3 years.
I have a Mahindra 1625 (25hp) and a 5 ft brush hog. Slow and easy works fine. As for getting the pot shaft off, mine slides on 1/2 way and I have to depress the lock pin again (or just hold it all the way) to slide it the rest of the way on. Same getting it off. I press the button and slide...