The stumpy is a great little atty. I'm running one with a single 26g 2mm ID, side mounted (close to the air intake) on a Sunbox. The thing screams vapor and flavour, both of which surprised the heck out of me.
The build couldn't be easier, and the results put many another atty to shame. I tried the overhead monocoil that Russ and others champion and it's very good, but not appreciably better than the simple single side coil.
Is it better than the Derringer? I'd say slightly, in terms of flavour, dead tie for vapor production, and definitely with respect to build flexibility (more deck space to play with). There's also a reduced chance of post loosening/rotation due to the design.