Pros
ZMP has very interesting projects and some good results in the robotics business but it is shadowed by serious issues. The company has kind people and there are a few engineers with experience in robotics. Field tests are regular in most teams so you can get out and have fun outside the office. A nice thing is that there are people from all over the world, so the company is very multi-cultural. ZMP can be a good place to start if you have no experience or if you are looking for an opportunity in Japan from outside.
Cons
First and foremost: against as advertised, ZMP is NOT a startup (by the western sense) and NOT a self-driving car company. It is just a small traditional Japanese company: lots of administration, it is highly inefficient and lacks proper human/talent management. It has way too many projects for only a handful engineers (lots of whom are inexperienced). The company mostly works like a university lab: no product management, lacks teamwork, code is often horrible quality, nobody cares about maintenance and they say yes to every offer/request that brings in money without thinking. The company distrusts its own employees which in return generates distrust in employees. Also, the office space is worse than most decent startups or well-going companies have.