Corrector Yui

Both are about Magical Girls. And both girls have a little helper always with them :] 

-Both are about magical girls fighting monsters -Both are very girly (To an extant) -Both have transformation sequences -Both have a talking sidekick in SM it is a cat in CY it is a robot  

both have a fairly similar atmosphere, and in both shows, the main female leads have to receive missing items. 

The atmosphere, style and colors used for both anime feel similar. The main characters are very similar to one another in their attitude, with their cheerful personalities being the star of the show.  

- Both of them focus on a virtual world that is usually accessed by uploading one's consciousness via some kind of headset interface. - Surprisingly, both of them also address the theme of "uploading" one's consciousness online and the dangers and consequences that may come from it. 

both magical girl anime and they both transform Amu and yui are both very sweet girls who always want to help everyone and they try to se the best in their opponents, their good side 

Both series have computer-illiterate main characters that can travel to the 'net in order to help when strange things are happening. 

both sci-fi/cyberpunk magical girls 

Both main characters are very similar, they both believe in the goodness of the bad guy. they can transform using the help of their comrades, each of them with a different power therefore different outfits