Pros
1. Work on new technology (de-dup disk based backup storage system). The technology is way ahead of competitors. This can be fun to work for.
2. Some smart engineers and overall good engineering team.
3. If you joined before IPO, it can be a reason to keep working for this company until your shares are vested or its stock tanks.
Cons
1. Not much oppotunities moving up as engineers. In general, engineer managers do not talk about your personal growth too much during review or other times. They care more about getting things done. So unless you are good at kissup or very aggressive (gain favorites from certain higher level managers), your chance of promotion is slim.
2. Mediocre compensation/benefits. There is no 401K match. Quite mediocre health benefits requiring big out-of-pocket cost and monthly premium. There is no bonus. Only recently there is yearly stock option grant (earlier on, only after almost 4 years), and amount of grant is not good.
3. Mediocre engineering management. Senior VP almost never talks to average engineers so engineers have no idea what he is doing and he is probably has no idea what engineers are thinking. Other lower level managers seem only interested in getting their piece of work done, ignoring all other aspects of people management.