Should be a very good tractor.. one thing you should check though. If you think you'll ever use a box blade or rear blade or boom pole, etc and will need a smooth 3 point lift, ask the dealer to put one on the tractor and try lifting it in small increments. The
L4600 has been noted to have a rough lifting 3 point, the same as the rest of the L series, and some of the MX's. Yours may be fine or you won't find it a problem, but it's driven some to trade in a very short time. Kubota can't seem to fix the problem, so don't let the dealer tell you they'll "fix it after you buy".
A slip clutch shouldn't be any problem. I take the shaft off mine for the winter so it doesn't rust too badly. In the spring, loosen the bolts and spin it a few times to clean the plates up and you're good to go. I usually take mine apart every couple years to clean it. A shear bolt IS maintenance-free, but you have to replace them when they break. Depending on your mowing conditions you might never have to replace one.
Good luck, let us know how it turns out!
Sean