I always preferred the Gilbert erector sets.
Mecanno brand has programmable robots, but not the range of sensors that Mindstorms had.
Sometimes I'll get from ebay one of the battered metal boxes they came in. They make nice nostalgic decorations.
The web site and order system is in German, but I've been able to talk to their friendly customer service in English. Then there's the matter of shipping outside of Europe... but it's still much easier than scraping parts together from vintage Meccano vendors with circa-1995-style web sites.
I remember having some Erector sets as a kid in the '90s (they had merged with Meccano long before, and the choice of which brand to appear on which set seems to have been random since then), but these days the official Meccano/Erector selection is almost non-existent -- there are maybe a dozen small self-contained model vehicle kits, and you can't order generic kits or parts in bulk. It is rather sad -- these brands were once used for serious engineering prototyping and scientific work: https://en.wikipedia.org/wiki/Differential_analyser#Use_of_M...
The official Meccano-brand sets here in Argentina are indeed very limited.
I would guess Mindstorms gives more of an intro to programming, while Erector is better for mechanical engineering.
(also, hey! I was that weird kid at Handmade Seattle last year who asked to shake your hand :) )
It was a pleasure to meet you!
P.S. My mom told me that I couldn't handle the tiny screws used to put the Erector sets together. She was wrong :-) I spent endless hours building things with it.