Underrated? I bet 5% of the population have never even heard of. Can't be underrated if nobody knows who you are. By what you've listed sounds like you like the writer more than the director.
Meaning 95% have heard of them?
Anyways, now that you have heard of them (and you probably have heard The Soska Sisters get thrown around in the See No Evil sequel thread) this is a chance to find out if these up & coming directors are worth a damn. James Gunn, Trey Parker, & Matt Stone all got their start at Troma, and none of them have the ability of Steven Kostanski & his team Astron-6.
And when talking about movies that have a $1000CDN budget(like Manborg, a property that managed its own comic book, and even action figures from Good Leg Toys), writer, director, special effects manager, and editor are all the same person.