Best Bang for your Buck?
Most of the tree spade specs offered by the manufacturers are understated in weight, that is, if they say it weighs 1500 lbs, you can be sure it's at least 10% more than that, so be careful when checking out any of them as you may not have enough lift capacity to lift the tree out of the ground once it's in the spade!
Weight considerations aside, the old, pre-redesign Caretree spades are better than the newer ones. The new design was ill-conceived according to some that worked there, and had numerous warranty issues that never were resolved. As a result, they went out of business. The late model Caretrees just before the redesign were excellent machines, and if in reasonable shape when you buy one, should last for many years. Parts are still available through some ex-employees that bought up spares and manufacture some others themselves.
I believe their name is Pritchard's who also deal in Optimal spades.