Elwood, I've had my GC2300 for a little over a year now. I use it mostly for mowing and moving snow (FEL, rear blade, and front blower). It has done those things and several others (adding drainage, dirt digging (w/ toothbar), ground prep (w/ boxblade), and a bunch of misc. transport of materials (w/ FEL)) admirably.
A few things to consider with tractors of this class. First and foremost, think about future tasks--those things that aren't right at your door now, but that you may want to do shortly down the road. Specifically, do you anticipate future need / want for a backhoe? Also, consider any 3PH tasks you might want to do. In hindsight, I didn't fully consider some of my chores. Now, at times, I wish for heavier implements (I've found ways to improvise) and position control. Finally, drive these beasts and figure out which layout works for you. I find the mix of using the hydro peddle and 3PH lever awkward at times. None of these things made the GC the wrong choice for me, but a little more thinking ahead of time definately might have changed which tractors were contenders.
Someone else said you're probably not going to go wrong among these three and that your relationship with the dealer is just as, if not more important than which tractor you choose. I agree. I felt snubbed at both JD dealers I visited. Kub and Massey were sold by the same dealer. They were easy to deal with and have stood by me, though there hasn't been a lot of need. Their service people know me by name and have been helpful every time I've called. I like my dealer and I believe they'll be there when I need them!
Click my profile to see my other posts. Feel free to PM me if you have any specific questions. Good luck with your decision!