I'm of the opinion that a measurement isn't valid unless the equipment is calibrated. Certainly, one has to work within their budget and you can make do with some limitations. Still, when accuracy is required, then the quality of measurement equipment is important.

So I dunno. If you're looking to get a rough idea of SPL, then one of these meters is probably OK. And you can compare two sound levels with it. But I don't think even an improved model is something I'd want to count on provide really accurate information.