I have fired a DE .50 and .357, and I'd have to say that I was very, very impressed with them. Of course, the weapon didn't malfunction at all while I was using it, but the accuracy of both is very high. With the .50 Cal, I was hitting a 6 inch by 6 inch target at 100 yards with relative ease.
The kick from both of them are actually pretty similar to a 9mm, I would imagine because the weapon is just so heavy. I would bet that you could be just as accurate with a quick 2nd shot from the DE than with a typical 9mm.
Just figured I'd throw that out there