Pros
most of the engineering team is technically good. One place where I see testers fixing bugs too. learn and experiment with new technologies and tools. - ThoughtWorks wants to work on cutting edge technologies only - meaning mostly web based applications / mobile applications - increases your market value
Cons
if you are considering joining ThoughtWorks be aware that the environment is highly political - especially in India offices. If you want to work on a project / technology that you want / like to learn then its at the mercy of the Professional Service Manager who is in-charge of resourcing people onto projects - so do not get into a confrontation with your PSM else it will prove to be detrimental to your career. Setting expectations is not done when you join a project so it becomes easier to blame a person later during the appraisal cycle. The management in India is trying to please their management team by trying to do extra ordinary things which actually doesn't make sense for most of us. Consulting in India is a big joke - Its actually becoming a training division.