Great tractor... have had my own for nearly two years now. I work the heck out of it: skidding logs, landscaping, fencing, mowing, digging, you name it.
Blew out the front end twice, due to not enough rear ballast. Ring gear was replaced first time, and complete new front end the second. My rears were filled from day one. 440lbs of rear wheel weights helped immensely, added with the new front end. No problems since.
I lift heavy loads with my grapple that were causing my rear end to come off the ground. If you can make sure your rear tires always have a good part of the load, you shouldn't have any front end problems. I also strap on my backhoe if I'm doing any really serious lifting (boulders, trees, etc...)
Aside from this issue, the tractor (and the local service) has been fantastic, and has paid for itself twice over in the time I've had it. My wife now wants a smaller one for herself, and she's a Kubota-bigot. Bah!
Make sure you torque all the wheel bolts when you get it delivered and a week or so after you've been using it, and monthly after that. They will loosen on you as they wear in. I had a front wheel fall off in the middle of a muddy field shortly after getting the thing... I was not a happy camper after 'swimming' to shore to grab a big socket and torque wrench from the garage.
Enjoy your new toy... I sure enjoy mine.