Same here, bought a like-new 20ga, 26" Silver Mallard off a guy who had it fitted with a short custom stock for his wife. He threw in 18 boxes of shells and an extended Briley CYL choke. I told him it was gonna cost me money to replace the stock, and offered $400 which he took. So I ordered a replacement, basic stock from MGW and was shocked to open the box and find a really nice NRA edition stock. I extended the LOP 15" and added a Beretta MicroCore pad. Then I found a brand new still in the Beretta box 28" barrel for $173 shipped, and bought a lightly used set of Beretta/Briley extended chokes for it, MOD, LM, and IC. That same year I shot my second 25 straight in skeet with it using 7.5 shot.I have the matching set, 12 and 20 gauge 390 Silver Mallards. Great guns.
I liked it so much, I saw a 12ga on GunBroker and bought it, it's a 28" for $750. That was about 5 years ago.
I rotate my clays shooting between the 390's, my Maxus Sporting, and the 686 SP1.
Honestly, I find them easy to clean. Nothing to it once you figure it out. I clean my 390's along with my friends A300 and they are very similar.