The Ghostly Gun has been a solid starter for me and I think is significantly under-rated due to his cost and the misconception that you are going to be "throwing him away" due to his ability. So let's see if we can set the record straight a bit...

A typical 2-stud character costs 5 with 1 upkeep, so the question we need to look at is, does he offer enough to pay an extra 2 rock?

First, he has a higher than average Influence, which is harder to come by in the 4th Ring than usual. He also sports a high value that put him out of typical Shotgun/Soul Blast range.

Being an Abomination is a small benefit since you can fetch him with Raising Hell, but I would expect more synergy with this trait in the future so that eventually it will pay off more.

And then finally, his ability. A lot of people seem to think you're going to be triggering it all the time and losing 7 rock every time he gets into a shootout. This is entirely the wrong way to look at him. You're only going to use the resolution in a few instances. First, if he's alone and going to be aced, you can use the resolution to cut the shootout short so that he only gets discarded. This lets him come back later, and if 8's are part of your shooting structure it has benefits there as well. You can also use this to win a critical shootout, usually late in the game, where a wildcard can raise your hand several ranks, say from a 4-of-a-kind to 5-of-a-kind. I like to use Ace in the Hole in my deck as well so that I have a couple of options for manipulating my hand.

He's not someone you just throw into a deck, but with the right setup I haven't found anyone else to replace him without dropping my influence or leaving me without a solid starting shooter that's ready on the first action to defend against Kidnappin', etc...