Dealer reputation and service after the sale are critical, also parts availability, stock on hand, etc. Horsepower is your friend, CUTs are great machines, but more power is a good thing. Sit on them drive them around the lot and speak with people that already have them if you can. This forum is a great place to learn, but take it all with a large grain of salt. I cleaned out the edges of a large pond with my MX, but only the very edges. I managed to get the tractor stuck while doing so, luckily my wife was able to pull me out with a 4WD truck and a very long tow cable. The excavator for pond work is a good idea.