Pros
Wonderful, incredibly talented people. Sink-or-swim environment is daunting at first, but can be rewarding. Minimal micromanagement. One of the most forward-thinking companies in the industry (almost to a fault). Very innovative products that are fun to work on. Excellent work environment with great parties. Nightly music jams. Halloween is a blast for your entire family. Depending on the gig, telecommuting may not be a problem. Pretty flexible hours. One of two original founders is the new CEO, and will hopefully return Line 6 to its roots.
Cons
A lot of turnover, but sometimes due to sniping by bigger companies, like Apple and JPL. Development slows to a crawl after each exodus, and workload increases. Poorly-implemented Agile practices from influx of ex-AVID employees (most of whom have since exited) continue to leave scars.