"Great culture, kind and competent colleagues"

Pros:

The culture is the big one. People are kind and genuinely competent, and the company clearly values its employees. There are real opportunities for feedback, and for growth both personally and technically. Management actively tries to find you interesting assignments and clients rather than just filling a seat.

Contras:

Genuinely struggling to name any real downsides, and I'd rather say that than invent complaints. The usual consultancy admin (time reporting) is the only recurring annoyance I can think of, and it's minor.