Windows CE is an embedded OS, devs are expected to customize it for their device and application - it's more like a "kit" than something like PC Windows where there's one consistent OS with a consistent experience, whether the device is any good is going to be determined by what the developer built with the OS more than the OS itself. Though I wouldn't trust any device that advertises itself as being built on Windows CE (like, why should I care?) rather than just being a good GPS or whatever