If you are a fan of GANTZ creator Hiroya Oku then this a must for you. I really enjoyed this anime, its themes, and its many ups and downs. If you are familiar with Hiroya Oku this anime has his strange, tangental storytelling style. I feel like Hiroya Oku just throw darts at a wall. The biggest downside of this series is the SHIT CGI and very strange ending.
If you dig hyper-violence, robot action, and some existential themes about humanity I say go for it.