You can't really tell the long-term reliability of a device until it has been out in the world for a while. Big companies do (at least they should do) HALT testing to see how various components hold up. You can't possibly expect a small group like the Pandora team to shell out for something like that.
I'm sure the designers did everything they could to produce a reliable design, and there's a pretty good chance they succeeded. However, you should be prepared for the small chance of an unknown engineering issue cropping up. That's just the way stuff like this works.