1. Conflict of expertise. Analytical reports are prepared by analysts, not by private equity managers. The mindset, background, experience, and logic of a portfolio manager at the PE firm are much different from an analyst. Data that are important for you are useless for analysts. Analysts can reshape the focus of the analysis that makes the data and the conclusion opposite to the real situation. And opposite to the right decision as well.
2. Conflict of interest. Often banks prepare the analytical reports considering those companies covered by these reports who are the clients of these reports-makers. The conclusion is simple - the recommendation buy, hold or sell (which is issued to the market and commented on public media) is made based on an engagement letter signed between the bank (or expecting to sign that), prepared the report, and the client. The same we can say about reports of consulting companies and rating agencies. We solve this problem simply. We don't read them.
3. Low data reliability. Internet is the largest source of data and information. Hence, Internet never was a trustful data provider. You never know the source of the data for the prepared analytical report which you buy or download. However, in the vast majority of the cases, these are the data from the internet open sources, and sometimes already collected by somebody else. These "reports" study internet, not market. You don't want to make your decision on well blended trash, don't you?