Totally agree with waiting till you find something cheaper. They will come up. In the meantime if you have a job that needs to be done right now rent a mini-x. I waited and found a hoe (Different brand then my tractor - I modified the subframe/made brackets for approx $100 in steel plus my time) and that cost me half as much as a new hoe.
I also totally agree that while it's a great tool to have (It's on my tractor a surprising amount of time) it's no where near as effective as something like a mini-x or a "real" backhoe. But for the odd jobs I'm doing around my property it's awesome. Including post holes btw! I'm currently putting up a fence which is primarily running thru a forest - tons of roots and stones - I originally thought of renting a post hole digger, but decided to give the hoe a chance - glad I didn't rent anything, the hoe makes short work of roots that would have been a royal pain in the butt. Ya, it's a little bit more back-filling but for 30 plus holes I'm not bothered.
A strong subframe/solid tractor attachment bracket/points are the most important thing really. That is what will protect your tractor from the forces of the hoe. The hoe whether cheap or expensive will exert the same force on the tractor so it's how it's attached and ultimately how you use it that will dictate whether the tractor gets abused or not. Personally while I'm happy to hook the hoe up at any time, if a job came up that was going to require days of hard work I'd go rent a mini-x/backhoe - they will at that point be much more efficient and quicker. The rental will be money well spent.
E.