Currency: When was the information created or published? Do you need more current information?
Content: Is the information accurate? Does it provide in-depth information or just a summary?
Viewpoint: How does publication date, publisher, or other factors affect viewpoint? How opinionated is the piece?
Relevance: Is the information important for your needs? Do you need a source to get ideas or to cite in your paper?
Naturally companies want to present themselves as positively as possible, so will gloss over shortcomings or problems.
When reviewing company websites, consider:
External news articles and reports about your company can provide alternative viewpoints, which will help you develop a well-rounded analysis.