I've always wanted to buy a Mernickle but I can't bring myself to do it. To me it looks like there's nothing holding it in there but the barrel? A little more coverage on the top strap and I'd really like it. They make a field model with a bit more coverage, but there's other changes I don't like as well.
Here's an old photo of one of my Simply Rugged holsters. It's a whopper, half a cow though.
Big holster on a big gun. Top right is the way I use it the most.