This show immediately reminded me of Cardcaptor Sakura. It is the same idea, but much shorter and has 2 cute girls. A simple concept of fight the card's soul to recapture it, tossed in with some relation building between the 2 girls. Only 10 eps to a season makes it rather short with not much to say. Not a ton of stuff happens either though due this fact. About half the material is fighting these card spirits, the other 40% on the relation between Illya, Miyu, and the other 10% being at school/home/ or with Ruby/Sapphire/Rin/Luvia.
If you liked Cardcaptors, this is simply a modern day copy. Other than that, nothing unique, but it was still very enjoyable. It is nice to finally see the Cardcaptors type of anime again so that was a big influence to enjoyment.
The choice of characters is pretty typical, with Illya having a thing for her brother, and apparently maids. Miyu being a kuudere, which she says some pretty epic things in the last episode. Rin is a typical tsuntsun, and Luvia the typical himedere. However, Illya was too whiny for being a main character and gave up way too easily. This is the only part that really bugged me.
The graphics for combat were colorful and well done, same for sound/music.
There are about 4 scenes of Illya being naked (no parts showing) and a few suggestive scenes with maids/kissing/incest.