I got a pistol-gripped GL from my brother for a retirement gift in 2005. He got the straight-gripped one because of its cool look, but knew I didn't like them. He isn't much of a hunter and not much of a scattergunner either, so he gave it to his best friend, who is both.
I only use mine for hunting in areas where the ground is flattish and the shots likely to be open, like Kansas and the CA Coachella Valley and similar terrain. I'm not a target shooter.
The nice thing about the GL is that it's a 12 that you can carry all day. It DOES kick--I tried mine for two rounds of trap without the slip-on pad that I normally use (the factory LOP is a little short for my ape-hanger arms). At the end of the day, I thought "RUGER" must have been permanently stamped on my right shoulder.....
But with most bird hunting you don't shoot that much and it's nice to be able to walk for six hours and still be able to mount the gun while the birds are still in reasonable range. Always a compromise with shotguns.
Mine has probably shot a thousand rounds of field ammo since I got it and killed a lot of birds, pheasant, quail, partidges of both kinds, grouse ruffed and blue. I love it BUT (Mike's big butt):
It is too light for 3" magnums. I don't know why Ruger put 3" chambers on such a light gun, but unless your central nervous system is stronger than mine. magnums will induce a flinch.
The barrels are too thin for hunting in rocky terrain like our CA Coast Range canyons. If you whack those barrels on a boulder, you will at least need a real pro to remove the dent. If you whack the choke tube area, you may need a real genius to remove the tube and repair the area. The gun would be a perfect chukar killer except that making the barrels durable enough for rocky terrain would make it too heavy to chase those little bastards up and down the ridges. Compromise.
Mine has been absolutely mechanically reliable so far. I don't torture-test it with trap marathons and I keep it clean and remove and grease the tubes frequently. It all works like a charm.
Would I pay $3000 plus for one? I couldn't afford them when they were less than half that new. As much as I love mine as a gift, I'd say they were a great experiment like the Hawkeye handgun. While I'm glad Ruger made the effort, I think it was a noble failure.
I don't buy guns as "investments". My heirs can figure that dull stuff out--I shoot em all.
The real SHOOTING investment in Ruger shotguns is an RL 28. Not as pretty as a GL but a vicious little killer. They shoulda made it in stainless and called it "The Ermine."