I loved Meccano as a boy, and bought some for my son last Christmas - what a huge disappointment! As you said, it's plastic now instead of metal, and not even good quality plastic. It flexes too much, and soon showed white stress marks. Difficult or impossible to tighten things properly, one piece comes loose as you're tightening another.

Also, yes, the instructions for their building ideas were crap by comparison with Lego's.

I'm 100% certain it was a legitimate Meccano set, as we bought it at a brick and mortar toy store, not Amazon.

We stuck to Lego after that.