Of the 5 shotguns I've bought in the last few years, all are subgauge - 16, 20, two 28 ga. Only one is 12 ga - a side by side with 30" bbls. The only reason I bought that was because I shoot flyers at retriever field trials and I'm a traditionalist.* Historically, double guns were used. Other than that, I rarely shoot 12 ga anymore, even duck hunting. I'm going to be shooting a round of sporting clays this coming Saturday and I'm shooting my Browning XS Ultra .410 O/U with 30" tubes. I did that for the first time about 6 weeks ago and shot a 31/50.
*Most ducks/pheasants in retriever field trials are pre-killed, but there are always "flyers"; birds that are live, thrown upon being signaled by the judges and allowed to fly, then shot by two gunners. The other shotgun I use for flyers is my 12 ga Beretta 686 Onyx Sporting Clays model with 30" tubes.