Pros
The teams - co-workers are warm, enthusiastic and really into what they're doing. The agency does attract some really talented folk. The agency culture is a good mix - even though it's part of WT, an advertising network, it manages to promote work-life balance and a professional work environment. The ambition - the agency wants to do a lot more and expand into new avenues and business streams.
Cons
WTC has an impressive checklist of things to achieve - however, it is limited from achieving them simply because it hasn't spent time thinking of how to go about it. In some cases, you may be lucky to be hired for a role, only to be reassigned to responsibilities that may be very different from what you signed up for. This is because managers have to ensure you're billable; sometimes that comes at the cost of your ambition and learning.