Answer:
The best answer to the question: How can you judge the degree to which the authors are unbiased, would be: you must check if these authors work as consultants industry-wide, or if they work as contractors for a specific vendor.
Explanation:
When writing a report on the best vendors to choose from so that your company makes the best choice, especially when it comes to storing data from your cmpany, is a very serious thing, and the research done must be impeccable. As such, looking for information sources that will help guide you in your report, especially if the sources are online, becomes an analysis in itself on your part, as you must ensure the validity of the source you are selecting. In this case, you have found a white paper online that looks promising, but in order for you to be totally sure that it is the best source to use, then you must check the authors who wrote the paper, and most importantly, who they are working for. If they are consultants who do this for not one vendor in particular, but for the industry as a whole, they might be chosen as a reliable source; otherwise, you must not use them as they are not unbiased.