I was at a friend's house yesterday where she had ELC Marble Madness. I thought it was great, but it wouldn't have been the latest model (maybe 10-15 years old?).
I have a sneaking suspicion the quality has dropped based on the latest reviews I've seen of the product. It took normal tiger eye marbles this one I played with (although did notice it came supplied with small, plastic ones), but some silvery ones that looked the same size got stuck.
It didn't seem that flimsy in any case. I've read reviews of loads of runs and it seems Quadrilla are highly regarded, but they are pricey. They also look like they might fall down with just a slight knock, which in my mind would undo any fun derived from the sequences you can create. Then there's these Quercetti ones (two Qs with double letters... what are the chances?) that seem to be up there with the best of the plastics, but are again criticised for flimsiness.
Please help me with your real life experiences! Thanks.