American Splendor has opened up to rave reviews; the majority of critics 
  have called it an instant classic. While I do not understand where they’re 
  coming from, I cannot deny that it offers a great time, even if it isn’t a 
  great movie. A thoroughly amusing picture, this one perfectly combines 
  fabulous acting, stylish direction, and a witty and comedic script. Before 
  viewing American Splendor I knew little about Harvey Pekar and 
  even less about his comic book, but this only made it more enjoyable. Fans of 
  Pekar’s comic book, “American Splendor,” liked it because it was fresh, 
  unique, and breezy to read. I like this film because it is fresh, unique, and 
  breezy to view. Finally, I’ve found a comic book movie that doesn’t involve 
  any big, green monsters, grown men who have the power to shoot spider-webs out 
  of their wrists, or mutants in a school that teaches them how to become touch 
  with their powers. American Splendor is certainly the year’s 
  biggest delight 
       For those of you who don’t have any prior knowledge 
  on the topic, the comic book “American Splendor,” was written by Pekar (played 
  by both himself and Paul Giamatti in this movie), comically chronicling 
  everyday events in his life. For thirty years, he had a job as a file clerk at 
  a
  
  Cleveland hospital. Even when his comic book 
  began to sell, Pekar was never financially able to quit his day-job. Part 
  obsessive/compulsive, part control-freak, and part hopeless, his daily 
  adventures always intrigued readers. American Splendor is a 
  scrumptious showcase of all of the small journeys that Pekar embarked on 
  during the prime part of his life.
       The highlighting moments of American 
  Splendor are when the filmmakers merge clips of Giamatti acting and real 
  footage of Pekar, together. Through these, directors Shari Springer Berman and 
  Robert Pulcini and producer Ted Hope prove to us that their work is as 
  technically savvy as it is entertaining. It’s also amazing to observe how 
  accurate Giamatti’s portrayal of the real Pekar is. The transitions from acted 
  scenes to real footage are definitely noticeable, but succeed, from a creative 
  standpoint. The reason why they work is simple. Pekar was illustrated by many 
  different artists in his comic books. Each of these men drew him a different 
  way. When viewing American Splendor, we are supposed to feel like 
  we’re looking at the actual comic book. During the transitions, it seems as 
  though the “illustrator of the movie” has changed; we’re merely looking at a 
  new issue of the comic. The appearance of the character Harvey Pekar has 
  changed, but his personality has not. Giamatti clearly studied everything 
  about Pekar, prior to acting in this film. His performance is of 
  Oscar-quality.
       More tremendous acting comes from Hope Davis (who 
  was also great as the high-strung daughter in last year’s About 
  Schmidt).
  
  Davis plays off Giamatti’s character 
  beautifully; her work in American Splendor is darkly funny and 
  spectacularly interesting. Every single supporting performer in this movie is 
  superb. The reason why this movie is so fascinating is because of the way 
  Pekar interacts with all of the crazy, bubbly personalities that he 
  encounters. This film, really, makes me want to read a few issues of his comic 
  book and graphic novel.
       While it is one of the best movies of the year,
  American Splendor does not contain any groundbreaking material. 
  It offers a great time and is very accomplished, though. Everyone on this 
  project took risks (the directors’, writers’, producer’s, cast’s, and editor’s 
  work is extremely effective). Aside from a few fictitious elements, this 
  really is the true story of Pekar’s life, too. American Splendor 
  is definitely a movie to see; audiences of all sorts will be able to enjoy it. 
  Now I just have to work on getting the comic book geeks to buy tickets to it. 
  It’s amusing how most of them are resisting my recommendation, because this 
  one really shows us what underground comics are all about. It’s the most 
  enthralling picture I’ve seen all year.
  -Danny, Bucket Reviews