It's a very demanding work environment. If that's something you thrive on, it's not an issue (I worked with plenty of people that did) but if you're easily overwhelmed or need a lot of hand-holding, it's going to be bumpy ride (at least initially).
As a relatively small firm, it seemed somewhat common for the business take on a bit more work than the workforce can actively handle which leads to some early mornings / late nights. But this is true in the PR and marketing world in general, so expect some occasional infringement on your work/life balance.
Communication can be a bit fragmented. It's a place where you absolutely must take ownership over your work and actively communicate with everyone involved to ensure that nothing slips through the cracks.