Himouto! Umaru-chan is very similar to OreImo My Little Sister Can't Be This Cute.
Its a similar setup, blond girl is the perfect school princess. But is secretly an otaku.
Her older brother has black hair and is the only one who knows her secret.
The way these two anime differentiate is that Himouto is a fun anime with fun and likeable characters.
Whereas OreImo is the most atrocious thing ever.
This anime is funny. Every single character is great. The relationship and dynamic between the siblings Umaru and Taihei is funny and endearing.
Umaru's friends are all fun characters: Nana Ebina the best friend and neighbor with her southern accent she tries to hide. The scary but really shy Kirie Motoba. Even Umaru's rival Sylphinford Tachibana is written in a very fun way. And the list goes on.
The way Umaru seems to transform into a completely different creature whenever she enters her home is hilarious and cute.
A fun and cute anime thats definitely worth watching.