Pros
I was a contractor at Baker Technology and I really enjoyed it. They are a small and friendly gem of a consultancy. The projects I worked on were interesting and challenging. The people in the team were both highly skilled and fun to work with, and I was consistently amazed at how much we got done. The whole environment was optimised for delivering projects quickly. There was absolutely zero office politics and no admin to get in the way. The directors are techies at heart, and they value their development teams' productivity. They always worked hard to make sure that everything ran smoothly. I am proud of the work I did at Baker Technology and would have no hesitation recommending them to friends who were looking for their next contract.
Cons
I genuinely can't think of much to put in the cons section. The kitchen area was a bit basic I suppose, but the office is right in the middle of the City anyway, so it was no hardship to go outside for lunch or coffee!