This was a fantastic series and Ufotable (of The Garden of Sinners fame) was really able to show off their animation skills to the max here. This prequel to Fast/stay Night (which was made by Studio Deen) was leaps and bounds better than its predecessor in every aspect from story and pacing to animation, art and choreography. I watched Fate/stay Night first as I was told that watching it after Fate/Zero would just make it pale in comparison and I think this may be the best option (of course if you have the time, play the visual novel of Fate/Stay night instead). Even though I knew of some of the events to happen, Fate/Zero still kept me on my toes with unexpected twists and surprises. I also learned a lot more about the Fate universe and things from FSN made A LOT more sense after watching FZ as Ufotable did a much better job of explaining things than Studio Deen.

All the masters and servants get their fair share of back story and development and over time I really started to emphasize with each one of them. The dialogue and writing is fantastic in both the dub and sub versions. I loved the soundtrack too especially the first OP, "oath sign" by LiSA. Everything moved at a great pace and I couldn't wait to watch the next episode. Most importantly, this probably had the best action scenes that I've seen in any TV anime series (the Eva Rebuild and The Garden of Sinners of movies are on similar levels) so try to watch this on a big screen.

This show is definitely a must watch for anyone that enjoys a deep and compelling action-adventure anime. I'm really looking forward to Ufotable's remake of the FSN series (following Illya's arc I believe) that will be released in 2014. And definitely watch The Garden of Sinners movies as ManicB says. You won't regret it.