Not being very technical, I've tended to avoid devices but I'm stuck here in the US for a week and the local outdoor shop in Boston is selling these things for $149, which the currency converter tells me is about 77 quid or, to all intents and purposes, half what they cost in my local outdoor shop at home. The CX (I think) model is $249, or about 128 quid. Two questions. One, do I want one? And two, is it worth the extra 50 quid for the CX?