I picked up the Yukon Outfitters shotgun scabbard last time this sale came around. Yukon got several positive comments on the last woot+ sale, mine included. They know their stuff and are making good products. Here's my copypasta'd comment on the scabbard:
I'm using this with a Mossberg 500 with just a pistol grip (no stock). It fit quite well, feeling snug and kept in place without being too tight. The padding on the inside was nice, and I don't fear that it'll scratch the shotgun. Overall it was well constructed, and for the most part I'm quite happy with it.
For constructive criticism, there's only one main thing I would have liked to have seen. This would have been much nicer with a shoulder pad for the main strap. It's not bad without, but having one would have been a nice extra feature.
Conclusion: great product, especially for the price. As the Terminator says, I'll be back.