Microsoft

Microsoft engineers are very smart. Depending on the group, this can be a huge benefit. You'll find yourself learning from those around you (a good thing, unless you've got more ego than you deserve), and will be amazed at the capacity.

Microsoft is very heavy on process, generally. Some of it is understandable. Microsoft probably has more paying customers than any other tech company on the planet. This results in very high day-to-day 'taxes' involving enduring processes that are rarely reviewed for usefulness. This can be very frustrating.

A little more attention paid to true agility (not some mishmash of agile development practices layered over the top of the existing software processes already in place) would go a very long way.