This article provides a comparison between the MyISAM and InnoDB storage engines for MySQL. InnoDB is commonly considered to perform worse than MyISAM, but this article aims to dispel this myth by describing the differences between these engines and what makes InnoDB a good fit for many database needs.
In addition, a look at when it is better to use MyISAM and a case study of the drupal.org site provide insight for determining which engine is best for a given situation.