I made the grave mistake of purchasing a used Lulzbot TAZ5 late last year. I never got a good print out of it no matter what I tried. It would not print PLA - it would always clog the extruder, so I was resigned to ABS. Well, of course ABS has its issues - won't adhere to bed, shrinkage at bed, etc. that can be mitigated by painting a thin coat of ABS/Acetone, then constructing an enclosure with a heat source to get the build chamber up to 160F. That at least worked for a while, until the "Y" scaling issue appeared - a 1" x 1" x 1" cube ended up as a 1" x 1.26" x 1" cube.
So to "fix" this I ended up replacing almost every component on the TAZ, step-by-step without success:
RAMBo (motherboard)
LCD Display
Y Stepper Motor
Y Stop Switch
Y carriage bearings
New Extruder
New control box (including all of the wiring)
New external harnesses.
Nothing worked, so I have a useless machine that only cost me $1600 plus over 250 man hours

Next up, my 3D Systems Cubepro Trio:
Can't get a good print, always, always, always a filament feed error. Replaced hot ends and tried several new filaments. Can't get first layer to adhere on first, second, third, fourth, maybe on fifth try. Then secondary printhead scrapes filament off the bed. Can only use one head. Never got dissolvable filament to print (would start, then goo-up, then stop throughout the build process eventually cutting out and causing a "filament error")

Similar issues with my 3D Systems' Cube 3.

So my question is this; Does a "working" FFF printer even exist? I've now tried two MAJOR vendors that have moderate to high-priced products (no cheepo stuff here!). I've seen prints that look good from others, but my personal experience demonstrates that they either got lucky or the "good looking prints" were a 5th, 6th, or nth attempt that finally looked presentable.

Seriously, is there a unit that works, as advertised, out-of-the-box, every time (well at least 80% of the time)? Or should I just give-up?