Sing Yesterday for me may have bad sides, but is nonetheless very enjoyable to read. Frankly I don't know what made me like it since a lot of things arn't great, but I liked it. Maybe it's the feeling on how the characters live and evolve, maybe it's the characters themselves (Haru has such a cute personality), maybe the art style, maybe the grunge clothes ( yeah i really like grunge), or maybe I just like everyday life manga. One thing is sure, I recommend it happily to anyone with a bit of maturity. So if you like any of these characteristics, you probably will like this manga, unfortunately not very popular.