Pros
Spotify genuinely cares about is employees and it shows. They invest in employees with a week long "intro days" trip to Stockholm hq. The organization is relatively flat with opportunities to move laterally and try new things as well as grow your career and responsibilities. There is very little resistance from the org if you want to invest time and energy. Hack time is great and well respected by the company from the top down, including a hack day usually every 2 weeks and a full organized hack week every so often. There is a strong ethic of questioning things, even well established things and making sure that ideas still pass the test. There is some really top notch engineering talent and few people who are not at least very good engineers. Food is really good. Plenty of good options for breakfast and lunch and often there is food to be had for dinner as well and plenty of beverages, including iced coffee, espresso and a good selection of beers.
Cons
The technology infrastructure and client are pretty well established and a lot technology decisions are all already made. There is some pretty strong resistance to introducing new technology for fairly legitimate reasons. Spotify is really becoming a data driven company and there some excellent opportunities for data engineering. There are too many internal quirky libraries and systems that could be better served by using something open source or more standard. This seems to have been recognized and this is gradually being phased out. Benefits could be a little stronger like paid transportation and gym memberships for instance would really be nice.