OK, well I retired 3 yrs ago, many years as a foreman/estimator/project manager and heavy equipment operator. I have spent considerable time on pretty much any excavation/grading machines, finish grader to D9, 345 excavator etc. Track loaders were the digging/ demo rigs for a long time before excavators took over, you can throw a lot of dirt with a 345, and great for training truck drivers- you can really rock their world to get their attention lol... I always have a few tractors around, and still have my Case 680E that I traded a wrecked pickup for, the only reason I have it- Case stands for Can't Afford Something Else. They sold thousands of them by offering great financing, but they have always been a little light on durability. Later Deeres have the advantage of an electrical/gear parking brake, so you can engage the 4x4 and lock the brakes, and it will let you dig hard without the machine moving. If you ever get the chance to use a Deere 710, they are beasts, like a small excavator on wheels. CAT BHLs have also become very good units, and the 210 skiploaders are unbeatable, and are the industry standard for large contractors. One thing about buying an older unit, if you get lucky enough to find a privately owned rig that was pampered, kept inside etc., that's great. If you have a kinda tobacco road rig, they are like a boat, when they sit around, things go wrong, and the longer it sits, the more you will have to work on it, and a single major component failure can cost more than it's worth to fix.. The newer track skid steers and mini-excavators are extremely handy, but not cheap to purchase a good one, you can easily spend $40-$50K for a clean one, plus attachments. Being handy and able to diagnose and make repairs can greatly improve your buying power. One can also get fairly new stuff from rental company sales, but look 'em over very carefully, they don't get treated very well lol... BTW, I once dug for a septic tank with one of those Massey add-on backhoe rigs, a 205 Diesel- man, it took a while, but I did get it done