In regards to the Vitamin C content, there can be many different factors that affect Vitamin C levels including; adding ascorbic acid, different extraction process, other ingredients, the amount per serving, using the whole berry vs. only the pulp, etc. We cannot speak to what other companies do, but we can tell you about ours.
Our E3 Camu Camu powder is certified Organic, and is derived from the whole berry which provides not only Vitamin C, but antioxidants and other nutrients. The full capacity of antioxidant and anti-inflammatory properties are available only when the entire berry is crushed and dried. This means the skin, the pulp and the seeds. Camu Camu is often thought about for Vitamin C, but just as important are the antioxidant and anti-inflammatory benefits.
There are many reasons why Camu Camu is a critical superfood for the body. Here is an interesting read (if you like to research further.) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4296744/