After getting VI I've found a bunch of new javelin units now, not just Kerns. I've never used them before, so I have no idea if they're worth going after and if so, how to use them.

What are they good at killing and what do they need to stay the hell away from? I'd also like thoughts on how many ranks deep they should be used with and such.

Also, what's the deal with their atrocious range? Do most Jav users increase the range via modding?