Scag doesn't have as many models in their line as some manufacturers do and the decision process is easier. Scag, like all the rest, do have variations of each model, so one needs to do their homework regardless. There are several angles to look at your situation. $16,000 is a chunk of change and you can buy almost two Tiger Cats for one diesel Turf Tiger. Staying with Tiger Cats streamlines your maintenance with the exception of blades should you change from the 52" deck size. The mower decks on Tiger Cats, Cheetahs and Turf Tigers are similar, the machines are somewhat different from each other. Tiger Cats have pumps and wheel motors with a common oil reservoir as do the Turf Tigers. Turf Tigers have higher output pumps with matching wheel motors. Cheetahs on the other hand have individual hydrostatic drive units, ZT3400 or ZT 5400 depending on deck size, the ZT5400 being a two speed unit. Engine options with higher HP are different on the wider deck Cheetahs. They also have a common hydraulic reservoir for both drive units with separate oil filters on each drive unit. Tiger Cats and Cheetahs have vertical shaft engines whereas Turf Tigers have a horizontal shaft engine and this changes several things. The hydraulic pumps are sideways which is not a big deal and driven by a V belt that is accessible from above the machine frame and in front of the engine. The deck clutch is also on the front of the engine. The deck drive V belt drives a 90 degree gearbox, a drive shaft, another 90 degree gearbox, then a V belt to drive the deck and its V belt. Although this system has proven itself, there is more maintenance required and more parts should something fail. The addition of a diesel engine adds another type of fuel is needed to be stored, identified and transported. Confusion between gasoline and diesel fuel has been a problem for some operators. I see more Cheetahs on trailers recently, some operators have replaced older Turf Tigers with Cheetahs. I haven't heard any recent comments about Cheetahs verses Turf Tigers. There are still a lot of Turf Tigers in my area, some are older models, and I have repowered several for operators. So do your homework, think about it and give yourself some time to make a sound decision. 48 month no interest financing is very attractive!!!!