Ok really this is the last time i talk about this...
in spoken english, way out sounds more friendly and less awkward. "where's the way out?" vs "where is the exit?" take it out of conversation and put it on a sign without the context, [way out] and you introduce a little less clarity.
IIRC, expo and m-line uses the term 'out'.
I agree that there should be uniformity thru-out the system. 'out' would be good, 'exit' even a little more clear.
my personal bias? 'way-out reminds me of that stupid flintstones episode. I blame fred.....