I don't really need to say much about this jersey. If you don't know why it's important, then I can't really help you.
I will say that this was the first Mitchell and Ness jersey I bought, way back in 1997. You may notice the patch on the left sleeve -- that's MLB's official Jackie Robinson 50th anniversary patch, which I picked up at Shea Stadium during a Mets-Dodgers game. I know adding it to the jersey technically makes the jersey less authentic, but I didn't care about that when I was 17, and honestly I don't care about it now. It just looks cool.
MLB's annual Jackie Robinson Day is this Friday, and I really wish I could be at a game that day, but the geniuses at MLB's scheduling office have the Mets playing a 3-game set in Atlanta starting that day (that series is wedged in between 13 home games for New York... nice job making that schedule, guys!).