I use Dead Ringer beard buster ghost ring sights, and love the sight picture. I have the ring positioned far enough out the rib so it shows me my 20" circle at 40yards, 15" @ 30yards, 10" at 20yards, etc... I love having the ability to picture my pattern wherever I lay the sights, no matter the range. Although the sights have a great picture, they have a few major design flaws. They're only adjustable for windage, and the windage adjustment isn't precise. You basically loosen the screws and slide it around to where you think you're close and fire a shot. And during all the adjusting you find the second design flaw, poor quality screws. The heads strip out of them like they're made of butter. They're an extremely small allen head. Luckily mine stripped out once I had them set up where I wanted them.
Had I known these things beforehand it may have been a deal breaker, but now that I have them I will try and work with them, because I do love the sight picture. I tweak most of my stuff anyway, so I plan on upgrading these screws with some quality machine screws, and finding a way to get these adjustable for elevation. Mine shoot about 7 inches high from POA to the densest part of my pattern, but dead on windage.