I can take it or leave it. Honestly after you use any system long enough you know it well enough it just doesn't matter. I've used both so much on cars that I can do the conversions (the "practical" ones: 13 mm is a "big" 1/2, etc) in my sleep.
What was fun was helping my friend and his buddy (both from India, so of course familiar only with metric) build his deck. Construction is still done in "American" standard of course... Trying to get them to wrap their heads around fractional inches was the hard part. They're both computer geeks too (like me) so they have no excuse, fractional inches work perfectly in binary (3 and 9/16 = 11.1001)
. Better in fact than decimal fractions.