Microsoft

1. Very smart, knowledgeable coworkers. You can definitely learn from your teammates.

2. Many interesting projects to choose from. No matter what part of computer science you are interested in, there's some group working on it.

3. Top-notch development tools and other software at work.

4. Better than average pay, great benefits.

5. Free MSDN Ultimate subscription for employees means you can get almost every Microsoft software product free for your home use. Deep discounts on Microsoft products at the company store when you are buying gifts for friends.

6. Most employees have their own office (though many new employees are doubled up), so you don't hear everyone's personal phone conversations at work.

1. If you are used to being the smartest and most capable developer in your company, that won't be true anymore. Your coworkers will be just as smart as you. This is hard for some people to deal with.

2. Arbitrary but Darwinian personnel evaluation process. This alienates a lot of good workers. Read the Vanity Fair article for details.

3. It's a really big company, so all the big company ills are present: lots of unnecessary process, empire building, and political (character) assassinations in the management ranks.

Scrap the evaluation system. If you put together a team of 10 superstars, you shouldn't have to torpedo one of the superstar's careers to fit an arbitrary curve.