While we do not use gamma seals on stored food, we do use them on our everyday supplies. We buy Brown and white sugar, flour, rolled oats, salt, and rice in bulk. Gamma Seal buckets work well in our pantry, allow easy stacking, and are convenient to access all while keeping critters out. Best of all, the lids can be removed by children without the likelihood of spills. For example, if an 8 year old is sent for 10 cups of flour, and the bucket has an older style lid on it, in my experience, you have a good chance of the bucket getting spilled over sometime during the flour bucket opening process.
They have also lasted far longer than we initially expected them to.
In short, for our uses, they work very well, and while the initial cost compared to new standard gasketed lids substantially higher, in my opinion they are well worth the expense if you are using them on a daily basis.
They work well enough that we have a few extra, just incase, they would ever be needed.