In my previous post on the merits of 4WD (MFWA I guess I should say) for utility tractors I left out maybe the biggest reason of all to get it - SAFETY.
A fellow tree guy (who just bought his second Mahindra, a 5500 4wd) and I were just comparing notes on this one.
Picture yourself going down an incline, doesn't have to be that much of one, with a load that is making you light in the rear. Now picture yourself picking up speed as your rear tires fail to put down enough traction to slow you down. Since your tractor has no front brakes, picture yourself now on a nice "Nantucket Sleighride". Now picture your new car, a child, or a steep drop-off at the end of the incline.
Sure, you might think fast enough to drop the loader in time to stop you before something bad happens, but things can happen pretty fast.
Having 4wd makes all the difference in this situation. All that weight in your loader gives the front wheels more traction to help keep you in control. (Of course, you have to already BE in 4wd - failing to do so is how I know about these thrill-rides).
I don't want to sound like a jerk, maybe it's too late, but please don't get 2wd just to save some money. Read a bunch of posts from many, many sources, like the ones in this thread saying that 4wd is a "must" for loader work. Maybe ask the dealer for the name and number of the previous owners of the tractors you mentioned, and ask them why they traded in their 2WD tractors. Maybe they took one thrill-ride too many.
Bird said it very well in one of his posts. The vast majority of the time you'll do fine with 2wd. The other times, you'll be kicking yourself wondering why on earth you didn't get it. It just seems to me that those "other times" will be enough to put a great big damper on your tractoring experience, and it seems to me that life's too short for stuff like that.
Ok, I'll shut up now.