I've benefitted from the MY stuff twice, in two very different ways.
1) I bought a Dodge Shadow through the US Military Purchase Program in September 1990, under the assumption that I'd be home from Germany in a few months (the Gulf War put a stop to that). This was just before the 1991 models were introduced. When I got stuck in Germany, Mopar offered to replace my 1990 model with a 1991 through a call to my parents, who were going to pick it up for me back in the States. Something in my head told me to say no, which I did (and my parents bitched about it). I wasn't a gearhead or pistonhead at the time (not even close), but there was something instinctual kicking in there. Turns out that Mopar ruined the Shadow (and even ruined the pre-ruined twin Plymouth Sundance) for the 1991 MY, slapping it with that imbecilic "America" tag and generally turning it into the piece of shit that's stained its rep since. My 1990 proudly sailed along until it was side-swiped by a truck in 1998 (of course, I rust-proofed it).
2) The piece of complete utter fail that was my 1995 Ford Windstar finally gave up the ghost in November 2007. That got traded in for my current vehicle, which, of course, is an MY2008. Since Honda put in some improved mechanicals and additional toys into the MY2008 compared to the 2007 Fits, I made out well. And, of course, in 2009 came the Mark II Fit, the likes of which has caused me shame that m'Fit is associated with it.
I'm used to the American system. I like the American system. I just think it can get a little ridiculous when you start introducing the next year's vehicles prior to, say, September. That's what we had in the old days: new TV season, new football season, and new car season were all simultaneous.