I bought mine a few months ago and just love it. It took a couple weeks to convince my Wal-Mart dept mgr that I was serious, but he finally called their wholesale house and those folks said 'sure, we can get that model (50485), you (the store) just need to add it as a special order item, no big deal'.
Well, it took a couple more weeks and then, one afternoon I was walked out of the store and handed this fine 20 ga 510 (less than $300.00 including tax). It comes with a coupon from Mossberg which offers great pricing on an adult sized stock, LOP to 14", which is just what I needed.
It now lives in the corner of the bedroom as the #2 home defense firearm, magazine of 3 Federal PD2564B #4 buck (no shell in barrel). I could not have asked for more for my HD application, sure, the grandkids will enjoy it, but it's a comfort to know it's there at the ready. My nearby public outdoor range has a shotgun area that allows 7-1/2 and smaller, so I have a place to have some fun.
This is the best HD shotgun, small, lightweight, easy to operate, even my wife can handle it, and is happy it's there, although we don't expect to ever fire it except at the range.
Just got my 510 Mini from BassPro. I bought the 20 gauge.