Yeah they are expensive, the used minis I've been looking at are in the 12 to 15,000 range for the 2 ton ones. I probably have 3 to 4 seasons of solid work to do between digging for a foundation, drainage, stump removal etc. But work is really slow and there is the wife factor lol. Starting to think a backhoe on my tractor is the smart option however mine is a small kubota so I need a bh 65, 650 or 6000. Hard to find.
I looked hard at backhoe attachments for my DK45 but could not talk myself into it. I used a larger older TLB we borrowed from a friend years ago to dig out old hardwood stumps in an area for a food plot. We cleared small planted pines that were at least 8 years old from that small plot, so I know the hardwood stumps had been rotting for at least 8 years, maybe more. It was a real chore to remove the stumps, I had to cut the roots on all 4 sides of a stump before I could pry it out with the TLB.
That experience convinced me that a backhoe attachment on my DK45 would not work well for hardwood stump removal. I kept going back to the idea, but kept talking myself out of it. Eventually, I decided to start looking at Mini-excavators. As you say, they are expensive. I was looking at machines similar to the ones you describe. I have limited mechanical skills. I tested a lot of different used mini's. I could not convince myself that anything in that price range was in good enough condition that it would not be in the shop a lot for repair. I figured I would be paying as much or more for fixing it than I would buying a more expensive machine in better condition.
It took me a long time to save up enough, but eventually I bought a JD 35G with a long arm and about 1,000 hours on it. It is a 3.5 ton unit. It pushes the limit for my 10K trailer when you add the long-arm, counter weight, and buckets. It quickly became apparent that my old 1998 Ford F150 was not up to the task. It struggled hauling my DK45 with equipment. I ended up getting an old Chevy diesel to haul it which increased my investment.
I will say, there are advantages and disadvantages of a mini-excavator for habitat work. On the plus side, it is a real advantage to move it quickly around the small area of a work site. Mine had a hydraulic thumb which I love for habitat work. Mine has 3 way angle blade which works well for pushing dirt back in the hole after removing a stump. With the thumb, you can pick up a stump and drop it to get most of the soil to fall off too.
The biggest down side I see is the transport time in the field. It is very slow. With a tractor, I take it to the work site each day and return it to the barn. With the mini, I take it to the work site and leave it until I'm done. That means I need someone to pick me up from the work site the first day and then take me back out the last day unless I want to walk it.
It was a large investment, but my plan is to use it for a few years and then sell it. I understand used ones seem to hold their value pretty well if kept in reasonable condition.