Pros
I work with some truly fantastic people - they make coming in and doing the work incredibly rewarding. Pay and benefits are roughly in-line with comparable companies/locations - based on the other reviews it seems like this may not be true for all employees. Food is catered in multiple times a week, snacks are provided (you won't go hungry!), and many of the offices have space to blow off steam (ping pong tables, etc.)
Cons
There is a bit of continued nepotism going on, in spite of Mirantis' growth. Retention of known bad employees who have "been around" for years is concerning, but appears to be (in some cases) reaching resolution now. Senior leadership is, at best, a lovable mess - and at worst, a micromanaging nightmare. The lack of effective strategy from the top down makes this infinitely worse - if you can't convey your vision for the rest of the company to rally around, how can you be sure we are contributing to it? It is not enough for the vision to be "sell OpenStack for money". That is what got Mirantis to its current position, but it's unlikely to survive the long-haul without a more focused audience and plan. Unfortunately, this boils down to a lot of smart people creating their own strategies and cabals inside of the company trying to "solve the problem" of successfully winning and wowing customers. It's a waste of resources and causes endless frustration as nobody makes much headway.