I don't know if it's realistic in its depiction of AF, I don't care - though I'm definately more interested in watching real football since having read ES21.
But a standard sports manga? I've only read Captain Tsubasa and a few Adachi's, but this was far from. It focused a lot more on the characters than the former, and a lot more on exciting battles [matches] than the latter, which made for an extremely entertaining read.
The stuff I enjoyed the most is the standard-shounen "Will trumphs all" that the japanese are so fond of (and are actually one of the few personality-traits of that country I thoroughly like). Thing is, its execution was extremely well-written. Hopes, ambitions, dreams, the desire to stand at the top - things that any self-respecting male has. The Devil Bats had them, but they were not alone. The opposing teams had them too, and whichever team's dreams were crushed, I felt it, both in the emotional script and the vibrant drawings. I usually prefer if a manga's author and artist are the same, but these were on the same page throughout.
Proper Bromance. Hopes, ambitions, dreams and desire to stand at the top are always more entertaining and Beautiful than "S/he loves me, s/he loves me not."
As a side-note, ES21 contained some of the more entertaining, albeit clichéd, characters I've seen. Again, it's not about originality, it's about EXECUTION.
I hate when people give out tens to everything. But for me, this was perfect. Maybe I will change my mind after reading more sports - I know more experience led me to conclude that Devil & Devil was not quite as good as I had remembered- but for now, for me, this is the ultimate sports-manga. One I enjoyed non-stop from beginning to end in more ways than two.
P.s. It was really fucking funny.