Pros
1) While I was working in Newtecnic, I met some very talented people. Due to the fact that Newtecnic is getting invovled in some very prestigious projects, is managing to attract very skillful (young) people to work for them.
2) You are taking a taste from some huge projects. Even from a sub-contractor's view.
Cons
1) Signing "fixed-term contracts" for permanent roles is a joke. Following Zaha Hadid Architect's footsteps, the company is aiming to have expendables employees. Great strategy, if you have market reliability and an attractive brand name that can work for you, in order to keep under control salaries and internal expenses. If you do not have, then the risk is always huge. Like ZHA's employees are saying, "go there, but do not invest and do not stay long."
2) If you think (1), then all the rest is quite logic. Working conditions possibly the worst you can find in Europe. No internet access, no company's email account, no socializing events, no team-spirit (between directors and employees), no benefits, no reward policy, no "real" personal development, no pension scheme, extra-hours and whatever else you can imagine. As I said, if you consider (1) then there is no point to add something more.