Pros
The cafeteria is fantastic. Delicious, plenty of variety, lots of healthy options. The kitchenettes throughout the building are great, too: thoughtful setup, good snack variety, plenty of drinks, and excellently maintained. The office space is very well designed. Good lighting, spacious layout, and lots of little nooks for when you want to get away from your desk. Ergonomic furniture, including standing desk setups, is easily available. Location is very commute-friendly. Corporate IT is shockingly good. On your first day you get a laptop that's perfectly set up. Network coverage is excellent everywhere. Video conferencing works reliably. Problems are rare and resolved quickly by friendly, competent support staff. Colleagues are generally smart, friendly, and pleasant to work with. They almost all love and care about the product they work on. Compensation is competitive, with a twice-yearly raise cycle, and benefits are solid. It's great to work at a company with such a prominent, meaningful product. If you can get something done at Twitter (which is by no means guaranteed) you can have enormous impact.
Cons
The management is implausibly bad. The CEO, Jack, is good at the "company figurehead" part of his role. But he simultaneously runs another large tech company, Square, meaning he runs Twitter in his spare time. He has 20-odd direct reports and no time to supervise them, so the executive level appears to be Lord of the Flies. That upper-management chaos of course trickles down. Everybody has a story of working hard for months on a project only to have it canceled at the last minute due to executive infighting, high-level turnover, or pure fickleness. Reorgs and emergencies are too frequent and frequently ineffective. The chaos also allows bad execs to thrive. Particularly terrible was Ed Ho, who runs the entire consumer-focused side of the company and can be seen in the news promoting Twitter with claims that, from the inside, appear at best stretched. Polite but cold in public, he's a dismissive, controlling jerk in private. He talks a good game about collaboration, but in practice he is widely know as a "my way or the highway" guy, forcing out dedicated, experienced contributors. He has steadily climbed the ranks, making it ever harder for people with different views or approaches to find ways to stay at Twitter. This managerial mess of course ends up creating technical messes. Twitter's feature velocity is much slower than comparable software shops due to extensive technical debt. Frequent priority changes leave plenty of junk behind in the code base. Engineers with promotion ambitions know that they'll be rewarded more for creating fancy new technology than doing mop-and-bucket work, making things worse. This drastically reduces the effectiveness of the many good engineers working there. One of my engineer colleagues said shipping software at Twitter was like "swimming in mud" compared with other companies they'd worked at. This was complimented and enabled by an HR organization that was at best unhelpful and lackadaisical. I understand that many large-company HR shops see themselves as there to help the company, not the workers. But even by that standard they were below average, eager to avoid engaging with anything. I know of at least one racial bias incident where they were very anxious to deny that there even could be a problem, suggesting without any investigation that it must be a misunderstanding. (Kudos, though to Blackbird, the African-American employee resource group, whose response was instant, vigorous, and appropriate.) Much of this might be forgivable if the organization were effective. But one of the striking things about Twitter is how little it gets done. Note, for example, that when a tweet gets popular, the tweeter will say something like "RIP my mentions!" The notifications interface, though, remains unchanged, useless at high volume. Or consider the lack of an ability to edit typos in tweets, an enormously popular request. Their big recent change is expanding tweets from 140 to 280 characters, hardly a technical miracle. And so many features get launched and then never touched. Compared with Facebook, which is continually tinkering and improving, Twitter gets so very little done. And few at Twitter even seem aware of the problem, let alone are willing to discuss it openly.
