I have one with 54' cutting deck and Kohler pro 25hp. It is speedy when you need to, so you save time. Last good experience was a piece of metal that goes behind the center blade under the cutting deck compartment fell off and, to my surprise, the cutting performance increased dramatically!
You see, that piece is important to cut garden grass neatly manicured, but when you have to deal with over-your-knees tall grass that is dense and with big roots, my GT 5OOO without that piece totally crushed that high grass at speed 3! I discovered that without this piece, the rate of discharge out of the cutting deck is completely untapped and it just cut like a big tractor with a 'taladora' on the back..so if you have one...KEEP IT! If not, just get it!