I was the biggest Derringer fanboy until i got my Samurai Bonsai RDAs... hands down slaughter the derringer in terms of flavor, ease of build, and options. I bought one of each of the two clones out on the market right now... the 1:1 and the the one that is 1:1 but the top "ring" is a few millimeters taller (and has a different insulator style).
You get that intense flavor because it's just as small as the derringer... but then everything else you get is so much better. I'm actually liking the clone that is a tad taller as it just seems to help the flavor for some reason. It comes with two "shower" caps, one short (pictured) one taller and the traditional top styled section that fits regular drip tips.
I wont be ordering an authentic as i prefer the "taller" clone over the 1:1; however, you simply can't go wrong with either clone or authentic.