THIS REVIEW CONTAINS SPOILERS
Almost every aspect was poor (3) for me. Let me elaborate. Please bear in mind that i kind of forgot a lot of things about this manga because i didn't like it so much, and that this is my own opinion so you shouldn't be err attacking me for it.
Story: i was very unimpressed with all arcs. let's just say all i remember is explosions. my favourite part in the story was reigen's character development (somewhere near the ending)
Art (4): obviously not the best art ever, i'm not going to trick myself into saying that the art is mediocre because a lot of manga have better art i believe
Character: i see that the ending was supposed to be character development for mob, but the problem is that i didn't feel like it was very interesting. exploding everything and crying? that's about it? i suppose reigen is an interesting character for helping mob out in the ending (i remember his dramatic part because i liked it), but bear in mind that this manga has other characters too... in the end, isn't everyone else kind of... unneeded? maybe i should reread the manga but this is what i remembered.
Enjoyment: i don't remember laughing a lot for the comedic parts with ekubo. even worse, i was looking forward to mob's character development but it just didn't suit my tastes in the end. i read every chapter as it got published so maybe the wait for it made me forget details? anyway, i do not remember enjoying the ending as well...
I think I had expectations that were too high, but i believe some may enjoy the read as seen from the other 10/10 reviews. if you really want to start MP100, i actually want to recommend watching the anime instead because the animations and sound are really cool. like... perhaps... award-winning cool.