Nothing breaks a machine better/faster than an ignorant (inexperienced) operator and an irresponsible owner, save for a mechanical defect. Asking a machine to do something it was not designed for is truly asking for it. Learn and know your machine's limitations. That being said, I think we all ask a "little extra" from our machines at times and get away with it.
Not sure where you heard that three-point mounts break tractors in half, if that were the case I doubt that type of mounting would be offered (reference operator error). A rigid top link eliminates the possibility of the hoe lifting up and back into the tractor and possibly injuring the operator.
Brands: Very few hoes are produced domestically anymore, and I can't state which ones because the market is so dynamic. In my opinion the good imports come from Italy, Korea, and Sweden, which are sometimes re-branded to American brands.
As for hydraulics, any of them can use the tractor's system or an independent PTO driven pump. The latter will be equipped with it's own reservoir - all should include an in-line return filter. Using the tractor's hydraulic system is the easiest when it comes to mounting/dismounting the hoe, just two quick connect couplers instead of man handling a PTO pump (I speak from experience). But then this all depends on how your tractor is plumbed.
