Microsoft

Quality of people is above everything else. The people working there are far above average in terms of skill. Everybody who works there for a longer period of time is there because they love and are seriously invested in some part of software engineering. If you are in it just for the money, you won't endure for long. Also, contrary to things I have heard before joining, people are more than willing to help even if they are extremely overwhelmed with work. That is something I must applaud.

Opportunity to work on truly uniquely large projects. I worked in the SQL team, developing a new service within Azure Data, and I must say the experience is quite something. You get to work with extremely big clients, educational systems of entire countries, etc.

Knowledge.

Firstly, it is mostly internal. While that is the case with most large companies, it must be mentioned. Secondly, internal documentation is extremely bad, virtually non-existent. Usually, it boils down to going through 20-year-old code, files of 10k lines or more, in order to get how things work. It is extremely tiresome.

Tooling.

Amount of time wasted on bugs with tools, simulators, and authentication is amazing. And unfortunately, even though everybody knows about it, it is expected that time you spend on those kinds of problems isn't included in regular working hours.

Take more care of your employees.