It's the Same, Now It Sucks: For a period in the mid 2000's, J.C. Staff was disliked by some due to a few of its shows having very similar main characters (Shakugan no Shana, Familiar of Zero, Toradora!). This isn't as much an issue now, though.
Visual Effects of Awesome: A lot of their works have great animation such as Food Wars, Flying Witch, Prison School, Shakugan no Shana, Little Busters!, Wixoss, and then some. Largely considered to be one of the best studios with great animation. Most likely due to how long they've been around.