Pros
Have been working with Crest for almost two years now with a great technology stack - Scala, Play, TDD and pair programming. Teams have been setup in a completely Agile setup which is very similar to what you find at ThoughtWorks. Some of the colleagues that we work/partner have been ExThoughtWorkers. Has a great team culture - where everyone can voice their opinions, no voice is unheard :) Be it the awesome team parties (mind you we do have an enormous number of them) or outings people are really noisy and have great fun. I am actually recommending people to come over and see how we actually work before going with any of the reviews here.
Kontras
Glass door reviews can be intimidating but 95% of the reviews are from the PreMedia section of the company. The culture is completely different when it comes to IT division.