I just recently moved from Android to an iPhone, and pretty much every teenager I've texted since has immediately texted back something along the lines of, "Wow, you got an iPhone. Cool. Welcome." My son had to explain to me how they knew I'd switched, as I had no prior clue about the green/blue message colors. A couple of crusty old middle aged folks like myself have commented as well, but not nearly universally like the teens.

So clearly the teens in my social circle at least are paying attention enough to notice and comment.