Boot Hill is a great example of a game that just isn't really MAME-able. Sure, you can play it in MAME, but it's just about the saddest graphics you'll ever see when all you're getting is the emulated B&W.
But the real thing with the mirror and all the artwork, really, really comes alive. There's just no way to recreate it on a PC monitor. You've just got to see the real thing to appreciate it.