Total Recommendations: 5
Both series involve a somewhat abnormal main character being dropped into a fantasy world. They make friends with a bunch of oddballs and go on a variety of comical adventures. Both main characters give a snarky running commentary on all the strange things happening around them, and tend to take a refreshingly pragmatic approach to getting things done.
Valkyrie Drive is Soul Eater NOT with orgasms basically.
Without spoiling anything, let's just say these two anime are almost identical in how they play out. Very different male leads obviously, but everything else is bizarrely similar.
Same basic plot, but gender inverted. (Well, to an extent. If Mayo Chiki was completely gender inverted there would be mass public outcry.) Both have gender bending shenanigans, and a lead that has a phobia of the opposite sex. Mayo Chiki is more ecchi, and Maria Holic takes itself a little less seriously.
Both revolve around an OP chick that loves fighting, and has a more or less unrequited crush on the relatively normal MC; whom they are protecting. Both of the females are very quirky and often do irrational things, causing their crush to act coldly towards them. The setting is different, but both anime have specific things in common.