I've had my 2wd 555E for ten years now and if I had it to do all over again, I would get 4wd. My land is fairly flat, red clay. During late spring into late fall, when the temps are warm, I can use it a day or two after it rains. I can't run it at all in the winter, the weight of it is too much for the ground and you either slide around, spin the rear tires or get stuck. Stuck means tearing up the ground and sometimes you lose a few trees pulling yourself out with the hoe stick. Then you have to wait well into summer for the ground to be dry enough to go back and fix it because all those ruts hold water long after everything else dries out. It also lacks traction for loading with the bucket. I've found it's faster to break up the ground with the hoe, then load it. I made the front bucket into a quick attach so it can use skid steer attachments and that's proven to be a great thing. The backhoe is big enough to take out any size tree. The loader can lift two tons, and with the grapple, that's most of what comes out. There is enough traction to drag the larger trees to the burn pile, but some of the bigger ones still have to have the root ball cut off and the dozer is used to push those to the burn pile. There isn't much that it wont do. My neighbor has 4wd on his backhoe. Same terrain, same soil, and he is out there all winter long. The difference is night and day in both traction and loading dirt.
Parts are getting harder to get. New Holland has them, but they want to sell you kits and parts to replace perfectly fine parts so the new repair parts will work. I've found that for cylinder repairs, it's better to go to a specialty shop that has all the gaskets and seals in stock and will sell them to me individually. It's anywhere from $20 to $60 for just the parts I need, or $200 to $400 for what New Holland has. I've also found that going to other specialty stores can save a lot of money and you end up with better parts. The starter is from somewhere in Eastern Europe and not very good. The replacement from New Holland is the same thing and will only last a few years. But I found a Bosch from a starter/alternator repair shop that was just a little more money that has lasted 6 or 7 years and is still going great.
Go with a brand that you have a dealer close by. They are all pretty similar in quality for the same years and hours. An 85 Case is just as good as a Deere, Cat, NH of the same year. All will have issues and all will require wrenching on them. Hoses will go the most often, so be sure to have a large selection of big wrenches. Mine go up to 2 inches, but that handles my dozer too.
Eddie