Amazon

You get to work on challenging problems and learn from some of the best engineers out there. There also tends to be a clear correlation between what you're working on and tangible business objectives. Also, individual development groups have a lot of autonomy in how they work. (This has its downsides; see below.)

Amazon's philosophy of minimal top-down policies on how work gets done leads to a lot of duplicated work, a lot of ways to do the same thing depending on which group you're working on, and a lot of confusion.

In general, I think the overall strategy for the company is proving to be successful. As far as leadership goes, though, there appears to be a little room for improvement in terms of giving more specific direction and guidance for how things get done.