I'm looking for a quality 10mm spacing, Euro Screw Terminal Block.
Never heard of "Euro Screw Terminal Block", Further I'm not sure what you mean by 10mm spacing. However if you mean panel mount terminal strips, the best I've used is the MK series, from:
https://catalog.weidmueller.com/catalog/Start.do?ObjectID=group7868124270769. Weidmuller makes some good stuff.
Not the garbage found from China as seen in blue.
Those things are soft (like milk jug plastic) and deform and bend especially when torquing down a wire.
Yes I've run into these basically a use once device.
Whilst mounting, the screw just pushes aside the plastic in the hole.
The result is the block pivots and never tightens down.
...
Whatever happened to quality?
It is available, but you will pay for it. I haven't purchased any of the MK series lately so I can't offer up even a guess at the price. In most cases I prefer DIN Rail mount terminal strips
Does anybody know of a reputable cost effective source, for what used to be good quality?
Well I just had to look up what we once used, which is Digikey #281-4070-ND at $13.07 a piece. This is a 10 circuit block in the small form factor, Weidmuller #0274620000 , in the MK series. They do have larger, this is just what I've used in the past. The bodies are a good hard thermoset plastic. I would suggest buying units that use at least two mounting screws. Weidmullers on line cataloging system sucks but hopefully you can suffer through it, but Digikey is faster if you know what you want.