Kichiku: Haha Shimai Choukyou Nikki

Both feature not your lame standard art/animation but are very distinct in that area. Also both have some actual plot and both deal with drugs. 

Both tells about a guy dealing with three woman, the characteristics of the woman are similar, namely the imouto, onee-san and milf. Both have happy ending, i guess. Jitaku Keibiin has a good animation but Haha Shinmai rich in plot, i guess. 

slimier art work with full scale female body and NO MOE SHIT 

almost the same Animation Quality Both Are Hentai Anime With Hot Female Girls  

Three females living with a single male. In Kanojo x Kanojo x Kanojo, the females are the one to open the first act. In Kichiku Hahah Shimai, the females are coerced and drugged instead. Both series had done in the blonde girl first. 

'Ijou Chitai' puts a girl on a money strapped position which end up giving her more than she bargain for. 'Kichiku' dominate in family matters and personal life where everything can change if a new figure is brought into the uniting family.