No, they aren't great at everything, but being the best at everything isn't what they're designed for. What they are designed for is to be functional tools, and like all good functional tools, they are designed to be durable and reliable, relatively maintenance-free, and to do most of what people need them to do. I know a guy who's been using his TI-83 for a decade, and it still works fine. I bought mine from a pawn shop for $40 three years ago, I use it nearly every day, and it works fine. The batteries in mine last... months. Actually, I think mine might be going on a year now. They're not pretty, and they aren't going to be able to do vector calculations in 3D, but as a tool, they're actually pretty goddamn awesome. And once you learn the UI, it's not that bad at all.