Spoiler-Free Verdict: It was fine. Better than Superman Returns. Stable--though unimpressive--foundation for a trilogy.
My issues with Man of Steel weren't with the overall plot or the adaptations they made to modernize his story for the big screen. The heart of the character was clear throughout the film (except at the end, see The Kicker below). I thought Henry Cavill made an excellent Big Blue. The setup for kryptonite was well handled. I liked exploring his childhood. I enjoyed the twist on the Fortress of Solitude, and the nods to several DC heroes, villains, and supporting cast. I normally hate the TV/Movie need to kill Jonathan Kent (which has never happened in the comics or the Animated Series), but I found this version both interesting and touching. My issues, and they are significant, were with the storytelling.