I have had a jukebox for about 6 months now. Mine does hang occasionally; I would estimate maybe once for every twenty hours of use.
It's more of a nuisance than anything; I just pop the batteries momentarily and then replace them and turn it on again. No data is lost or anything bad like that.
I've carry my jukebox in a small little caselogic case that I clip to my backpack as I trek around campus; when it does hang, it's usually after I've given it (unintentionally) a good jolt.
I wouldn't let the hanging issue dissuade you from considering the NJB; I really love mine.
<b>ßunn¥§troker 0wn§ j00!</b>