My attention was drawn to ReLIFE by a post at Blue Blue Wave, of all places. However, Papa Pixy warned that the anime has no ending and just stops midway, like Sacred Blacksmith. So, if you want to know how it went, you have to read the manga. So I did. And...
... the manga is not finished either. OTZ. But! It's designed to end, and it is progressing smoothly towards the finale. So, that part is not so bad, except that we cannot know what the mangaka has it mind for the resolution. Characters are pleasant, too. I could not put it down and essentially marathoned the whole thing over the course of several days.
Downsides? Mainly the lazy writing that uses convenient plot devices, such as evesdroping. But despite loving these crutches, some of the plot turns took me by surprise (especially ch.111).
So, Liked: Yes, Re-read: Yes. But one note of caution: the manga appears to be published in a direct-to-smartphone format, so it may be impossible to buy. I haven't investigated yet if the dead tree options exist.
UPDATE: I posted an additional Important Spoiler Note separately, because it really is a spoiler and Ani-nouto does not provide a mechanism for hiding of spoilers.