The designs are nice if nothing special, but the animation is amazing. Most anime has long, static shots -- but this anime has lots of movement in the background. Pay attention to the scene where Nanoha asks her parents' permission to keep the ferret as a pet: there is lots of subtle movement, which I found impressive for a mahou shoujo series aimed at younger kids. The transformation sequence is further proof of Arthur C. Clarke's famous quote that any sufficiently advanced technology is indistinguishable from magic.
Next was Rozen Maiden. Jun, a second-grader, is slowly turning into a recluse who spends his days shopping over the internet. His older sister tries to make him go out and go to school again, but Jun is quite rude to her. (If it were a sibling of me, I'd give him a swift kick in the nuts -- Jun certainly deserves that!) One day, Jun receives a doll -- a doll that talks and moves. She defends him when he is attacked by another doll shortly after being revived, and makes Jun her servant. She bosses him around, but sees that in his heart, he is a good kid.
This is a rather creepy series. The doll takes no shit from Jun, and bosses him around. Her face is quite serious, she never smiles -- and being enslaved to a doll who then feeds off your energy sounds like a pretty bad deal to me. Designs are nice, and the story could prove to be really interesting!