The US should absolutely step into line with the rest of the word and go metric. I find it astonishing that a country which prides itself on being ahead of the rest should lag so far behind in this one area - like half a century or more! There's a very strong case for world-wide standardisation - there have been cases of airline crashes which have resulted from misunderstandings of one measurement convention over another. I cannot give you a specific example - but my son is an air crash investigator and has told me this (he is not allowed to speak in specifics).
Metric is incredibly easy to use, and it's logical (in mathematical terms). Once you forget about converting, that is. Converting is like trying to speak in two languages at once.
Think of it like this: you can measure a line in any measurement-convention you like. It doesn't matter whether it's inches or centimetres or Whatchamacallits. You just count the lines on the ruler. Well, it's even easier than that with metric!
I grew up with Imperial measurements, and was well into adulthood when the metric system was introduced into Australia (41 years ago). I had no difficulty whatsoever with the changeover, and I'm seriously mathematically challenged. Even the older generation had no difficulty with it. You just measure out your ingredients until the numbers on the scales are the same as the numbers on the recipe! Our government sent every household a handy converter, and it worked like a dream, and still works. It's learned very quickly indeed.
The thing that most Americans find difficult is the conversions. They seem to have a poor concept of 'rounding', and try to work with impossible numbers, like '1.2345kg' of something. Ridiculous, in anybody's terms.