I have a lot of shotguns ( clay's and hunting ) in 12, 20, 28ga and .410 / but I have no need or desire to own a true "tactical" shotgun. I can go "tactical", if I had to, with any number of handguns I own.
For bird hunting - any barrel under 28" in length is just not going to give you the swing characteristics or the sight plane that you want when hunting. I'm not saying you won't hit anything with an 18" barrel / but it isn't the best or even 2nd best tool for the job.
If I could only afford one shotgun - for hunting, clays and if I needed it for Defense ..... it would probably be a Browning BPS 12ga, 28" barrel ( take the plug out and load 4 shells ). Its not a "Fighting" weapon / designed to go tactical - but it will certainly do the job for defense with 4 shells in it.