Pros
Interesting work: The consulting work is extremely diverse, ranging from high-level web pentests to low-level kernel and hypervisor vulnerability analysis. There is even a fair chunk of reverse engineering software and hardware work. One of the best things about being apart of the team there is that management makes an earnest effort to match people up with work that is interesting to them. In my case for instance I was consistently thrown into work covering my particular interests: C vulnerability analysis, binary analysis, reverse engineering custom network protocols etc. Great people: The Culture at Leviathan has a strong family feel, and is a place where anyone will find themselves among friends. Like any work-place there will be personalities that conflict, but I found that even in these situations people made an effort to overcome these conflicts and move forward in their professional relationships. The executives and management (CEO, COO, PM) are all extremely technical and have adept knowledge into security, the hacker culture etc. This is quite refreshing. Workflow: Low stress in terms of overall vibe. People aren't breathing down your neck. The work is typically interesting enough to where people finish it by means of their own passion and interest, if you aren't self-driven then your probably not a hacker anyway :). Leviathan has a hacker culture/feel all around. Likewise management understands that many hackers don't like to start work until 'the crack of noon'. Conferences: Leviathan encourages us to attend conferences and trainings. I spoke at several conferences while I was there, and Leviathan overed my trips to speak in Vegas which was awesome.
Cons
Location: The location doesn't have the best parking which can be difficult at times, but its not anything that can't be tolerated with a little patience :)