I've been lucky with the Zero Tail swing because other than struggling to move hydraulic lines, I have not been caught where I have need to have the counter weight removed to do service work, but that time is coming eventually after owning it near 10 years. I also have a funky diode in the alternator and the belt needs to be replaced, and I have no idea how the access it.
It has been a good machine, other than I had to repair a $4000 main valve. I was lucky to polish out the spool and just change the seals.
The Zero tail is great in the woods and tight places, just servicing is very tight. Older machines are like that. It is well built study machine like a CAT. CAT's don't spec the highest in class either but like Komatsu, they are smooth to operate. Like I said, my Komatsu could use more swing torque for side grading and has a cramped cab. I'ts a nice quality machine, quiet motor, I would not fear it, but If you could find a simple conventional machine, it may be the safer bet.
I regret not buying it sooner, and might have been better with a 12-14 ton machine. As my major digging is done, it is plenty for what I do, and I really should find more work for it.