4-wheel drive (FWD) is handy, particularly with a front end loader (FEL) heavily filled with whatever. I've FWD, but only use it when the FEL is into a dirt pile big time, and my rear wheels are "light" as a consequence, or when it's real muddy. FWD will tear up a wet lawn if you make a tight turn, but so will locking one rear wheel (boy, that make the tractor "turn on a dime", but sure will tear up the ground under the locked up wheel). The Kubotas, and most other tractors, let you stomp down (right foot on Kubota; dumb location as it is a real hassle if you are using the foot throttle) on a lever that locks up both rear wheels - such will get you out of most heavy mud and the like (I trust you are considering R-1 or R-4 tires, with "turf tires" forget about difficult traction situations, FWD or not). That said, I've managed, as most nut case tractor drivers, gotten into situations when locking the rear differential and FWD didn't quite suffice, and I needed the FEL to help me inch (literally) out of the muck. The option was walking over to a neighbor and asking for help (not a macho thing to do). So, FWD if you're doing more than mowing a pasture.