Buddy of mine chased parts to repair a Cat mini Ex, ended up DOOSAN machine rebranded, placed on the frame still had Burn't Orange/red paint.  One issue is Cat changes some fitting or thread sizes for their repair supplies and Doosan machines another size.  Rotary Joint was a major pain as failed and leaked terribly, Cat cannot get, Doosan was off thread, had to convert.

Might try a rent all for one 

Just quit dumping  pretty on O'l Darrel and he might come do your digging with the digger you already have.

If he stops you can thank me latter Darrel. But something says he will not.

Okay, here's my $2.63 worth:

I own a New Holland backhoe attachment, that is fitted to my D17 (series 1).

I own a Kubota BX1800, the slightly-less-engined version of the BX2300 that my Dad had, before he traded it for a newer BX-series.  Dad and I considered getting a backhoe attachment for our BX's, but we found that it would not dig as deep, or as well, as the New Holland on the D17, and the BX's agility with the backhoe attachment on, was of no significant advantage over the D17 with the NH.

Most of the BX hoe's ineffectiveness traces to the simple lack of weight of the BX tractor.  Mine has ballasted tires, 60lbs of iron on each wheel, and the front tires are filled with foam.  Asking the hoe to dig into anything stiffer than moist black dirt just resulted in getting kicked around in the seat... and the smallest bucket available did not improve it's pierce and cut capacity... the machine is just too light.  Trying to rip horizontally dragged the tractor around like a toy.  Trying to lift, flips the front end up, and the FEL's bucket does not curl back far enough when boom is down, to hold any significant additional counterweight.  We resorted to chaining a 225 slant-six Chrysler engine in the bucket to keep it under control, but the BX's small front wheels were crippled trying to maneuver the machine in a work area.

The BX series hydraulics use the transaxle as the reservoir, and the volume is not considerable.  The BX's main hydraulic pump is integrated into the transaxle housing directly below your left hip, and it's flow volume is very limited, so running hydraulics means throttle WFO, and when you're trying to be delicate, and work with a ground man, it's just not a great situation.

On a BX-series, you'll find a differential lock pedal.  IF you have a BX series, and want it to last, remove the diff lock pedal.  The mechanism of the diff lock is the #1 reason for all the BX series transaxle failures.  If you find a BX that has a crack in the bottom of the diff pan (particularly if it's been patched or filled with goop), the diff lock mechanism has broken, and pieces of the 'sausage pins' fell to the bottom, and got pushed through when the ring gear caught 'em.  The fix isn't cheap... usually it's a couple hundred less than the tractor's operational value.

An FEL doesn't do backhoe work, but depending on what you NEED to accomplish, a little ingenuity and some scraps will MAKE it capable of doing some impressive stuff, even excavating things that neither a backhoe nor a mini-ex can do...

But all this being said, there is NO machine that will get in, dig, swing, and dump spoils, then move, dig, and dump spoils, around a site, like a mini-ex can do.  Granted, a full-sized excavator can do all the digging, as long as getting in close, and working around obstructions isn't part of the requirement. The Mini-Ex can be put on a trailer and towed behind a pickup, where a full-size ex is an oversize load, and oftentimes, an overweight/permit required transport.

The TLB will mosey down a road.  My Kubota BX will make 9mph, and not a tiny bit more...  a mini ex is well... barely pedestrian.

A TLB will pick up and CARRY excavation spoils, but the FEL-only will do it faster, and better, because it isn't bogged down by the bulk of the hoe attachment.  About the only TLB I've ever run that would actually FEL materials with authority (as if there was no backhoe in the way) was the Case 580... and it has the added plus (if so found) of having the extend-a-hoe feature (collapsing dipper boom) for added reach... but nobody with a compact TLB setup would be able to make this work, as the boom weight gets too heavy (it eats up lifting capacity, and the leverage works against you).

And I realize this isn't answering question about brands and models...  I've used CAT, CASE, Bobcat, Doosan, Hitachi... a tiny, tiny Kubota and some other (brand I can't recall) of mini-excavator, and I cannot express any maintenance or long-term economy notes, because they were units I operated on jobsites, that were either brought in by others, or brought to me through a rental service.  They all operated well, got in, did the job, and left the site in one piece (albeit usually dirty).

I have taken my BX (with FEL) on jobsites... but I don't use it to DIG, usually to clean up debris, move snow and ice, push, pull or drag stuff out of my work area, and carry my tools (like a diesel-powered tool bucket).  I wouldn't trade that capacity for ANYTHING, but I wouldn't use it to dig a hole, even if it had a backhoe attachment.

The New Holland attachment on the D17 is SIGNIFICANTLY stronger than the BX hoe... but it isn't anywhere near as strong (by virtue of simple geometry) than a mini-ex.  The basic reality of excavation, is that the farther you are from the place where you're digging, the more mass, and the more power it takes, to accomplish the task.  Doesn't matter if the distance is horizontally or vertically far, the circumstance comes out about the same...  and that's why the MiniEx is good at what it does- it gets in really close.