Pros
Merixstudio gave me the possibility to grow as a programmer. I started as a Junior Frontend dev and got offered better opportunities as the company evolved. When I started were a ~20 people "creative agency", and now we're ~90 full-fledged software-house. After working here for around five years, I was promoted to Regular, Senior, Team Leader and now I am working as Head of Development. The company is pro-employee and is continuously looking for a way to improve its inner working culture. I must admit I have the pleasure to work with awesome people that are easy to go with and have a great sense of humor :) Then it comes to the technical aspects - as a software-house we work on a lot of various projects, mostly creating MVPs of new products. So there's almost no legacy code.
Cons
When transforming from "creative agency" to a software-house there were a few bumps along the read but that was around 3 years ago. Now the roadmap and vision are clear. Being a software house there is always a rotation in projects; you have around 2-3 different projects per year. This might not be a con depending on what you are looking for.