I've stayed with this brand because I like the overall performance. Just be careful to check the "+" and "-" signs when stacking.
But, as many reviews mention, the trays quickly develop cracks at the stress points. When I got the second set, I was extra-careful to twist/release as delicately as possible-- but after a couple of months, these are cracking too.
Please, please improve the design and materials to eliminate this serious flaw!