Apparently I still have baby brain. I bought Daytrex 2400, not Mainstay. At any rate, we tried them today and they're a hit. I liked them too, except for the dry, crumblieness. They killed my hunger pretty quick though.
The inner wrapping is like Saran wrap and I'm doubtful that they'll make it through a 1-2 year shelf life, but who knows.
At 200 calories a bar, they're more nutritionally dense than granola and Clif bars, but $8 for 12 makes them more expensive than granola bars and in the same ballpark as Clif bars.
They're OK but I'm on the fence about buying more. I don't think they're in much danger in the pantry but we'll see how the troops take to them.