Pros
If you need the freedom to be whatever you want, they will support you with it. It is good for people to pursue their passion. If you are proactive you will really succeed and be supported here. There are different types of projects and Social Impact initiatives you can work on. The company respects their employees a lot which is great. Perks are pretty great. You can attend conferences and take part in competitions and you have 100% TW support. If you are single and want to only focus on your career now, this is the job for you. You get to travel and learn a LOT. But you have to work your way up for good projects.
Cons
There is a lot of travel, getting on a flight every sunday night to a client site and back on thursday/friday evening. If you are not a travel person, this is not for you. They are pretty honest about the travel, but they say it depends on the client. If you are lucky you wont travel as much in the bay area is what I have heard. You can be on bench ("on beach" - thats what TWers call it) for longer than you want to be, then you are assigned to a local project till you don't even realize you are there to stay. They say they will work things out for you, they wont - they are a business and will think about what the business wants. They say the culture is great - doesnt work for everyone. Unless you are ThoughtWorky-crazy, you are not considered normal. Some of the consultants are nice and helpful, but watch out for some snobs who don't empathize with you not being from the same country as they might be. Some of them think its OK to be really mean making fun of your lack of cultural knowledge. The more arrogant and noisy you are the more influential in how things are done. They are a pretty tight knit group since they all travel across countries. This could also mean that words about you spreads faster than you have a chance to prove yourself. Dont fall for all the promises the recruiter might make that you will be getting a lot of training and you will get to work on a lot of great projects. Look beyond these false promises and decide whether your lifestyle would really suit this.