For shame, comments. No "Oh my god, they killed Dopey Bird" jokes?
Regarding the pacing, I think that this long wait is mostly a drag because we're waiting for them as they come out. As a final product, this'll probably be amazing. I've gone back and read through the martial arts tournament/Monster Association Attack arc a few times and it was much more enjoyable compared to reading it as it came out.
Between the quality of a work as it comes out, which lasts approximately a month per chapter, and the quality of the final product, which will last for effectively forever once it's completed, I'm fine with priority for the latter over the former.
Regarding how it compares to the webcomic, I actually really like the expansion each hero gets, as well as all the cool or attractive (*cough*Captain Mizuki*cough*) heroes that didn't even exist before. I remember wanting more of everyone as I read through the webcomic, and the manga is delivering.
That said, it's also true that this kinda takes away the punchline of the various jobber fights the S-class heroes got to show what they could do. Rather than making the S-Class heroes a reference to a type of hero, the manga just outright made them that character. It's a matter of preference whether you like this change or not, but both have their pros and cons.
