I have a few. I love them for plinking and just general nonsense. They get tossed into the console for road trips and the tackle box for river trips. They have their place. I have alot of nostalgia tied to a derringer thats why I have them.
I've fired one before .45 Colt and its oversized and heavy for what you get. I have a ADC M7 lightweight derringer in .380 ACP about the same size but weighs only 7 oz. I believe a J frame Centennial Airweight (442/642) would be more useful and quicker into operation.