They are the best alternative because you get essentially the same space and display features of glass tanks but the convenience of stackability. On top of that, the cages open from the front, so a lot of shy leos are more comfortable being handled because your hand is coming towards them on their level rather than from above.
Check out these brands:
herpcages.com (better if you use under tank heating)
precisioncaging.com (better if you use bulbs)
boaphileplastics.com (for large colonies)
LLL sells Vision cages, but crickets can actually climb up the sides of those.
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