Pros
Without a doubt, I learned at the fastest rate of my career while at TW. It's a place where you should simply drop your ego and treat everything as a educational opportunity. There are definitely others who share this approach, and if you can seek them out and avoid the excessively-opinionated people, it will change the way you think about technology. If you find a good project then milk it for all the knowledge you can, as the ratio appears to be about 3 bad (body-shopping etc) projects to 1 good one.
Cons
The humble people who like sharing knowledge are slowly but surely being swamped by inexperienced grads. This is directly attributable to the company's inexorable growth, which appears have reduced the hiring standards, and also appears to have no defined endpoint. All too often, passionate consultants are put into impossible situations on client sites, with TW management blithely assuming that they can affect change from the bottom up. On top of this many TW managers show no knowledge or interest in agile principles, and give you blank looks when you bring them up. Although the developers are probably some of the best in the business, unfortunately the same can't be said of the middle management (project managers and client principals), most of whom seem very generic
