Pros
I have been working at ScienceLogic for about a year now, and I have greatly enjoyed the experience so far. The biggest change between my current position and the last company I worked for is how much the company is growing. We have added a large number of people over the past few years, and expect to continue to expand over the coming year as well. There are also plenty of pending projects with customer demand, so I appreciate being able work in many different areas, and not being stuck on a particular piece of technology. Everyone in the company has been very approachable and willing to help me as I have come on board - from senior engineers all the way up to the CEO. The environment is professional, but flexible. Benefits were a step up from my previous job, which certainly helped.
Cons
Adding a large number of people into an organization does lead to some growing pains, so the development processes are continuing to evolve to fit the new organizational structures. But that is a pro as well, since we all have input into what those changes should be. The main con is an area which is largely outside of the control of the company - the traffic around Reston/DC. You must plan your travel into/out of the office carefully, or be prepared to sit and wait.