I highly recommend roaches, but only as part of a varied diet. Aside from having to use Vaseline, they are much easier and cleaner to raise than live crickets. You can use all life stages for various sized pets, including your gecko and bullfrog. The only problem I can say about them is their exoskeleton. Not only do they have sharp spines on their legs, but their carapace is especially thick. After performing a necropsy, I have reason to believe that the carapace of male hissers is responsible for the impaction and resultant death of a large bullfrog. My mistake was feeding the bullfrogs more than one cockroach at a time.
FYI: check out zoo med's "Can-o-" line of products. If you keep them frozen, they will last a long time and as long as you are diversifying the diet, you can provide them with hasslefree crickets, snails, and caterpillars that you otherwise would not be able to feed them!
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"I know the human being and fish can coexist peacefully."
Governor George W. Bush, Jr.
"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us."
Calvin and Hobbes (Scientific Progress Goes 'Boink', 1991)