This is an excellent program with a lot of potential. Keep in mind it is a version 1, and a very solid one. I do not use its collaboration features, so perhaps someone else can comment on those.
So far I have used it to organize my research, and to organize most of the information I have for a few projects I'm working on. This information includes PDF files, Text Clippings, Word and Excel Documents, images, etc, and in most cases Flow gives me an instant preview of the contents of these documents.
Prior to using Flow, I tried many products with some of Flow's features. Most of the programs I tried are actually pretty decent, although none comes close to having the versatility and capabilities that Flow has.
Customer support is superb. I really feel spoiled by their great service and support. For anyone interested in other reviews, just do a Google search. Little by little more people are finding out about Flow and praising this great software. Although I use it in a limited way, it's easy to see the amazing potential this program has. By the way, it pays to read the manual.
I'm giving price a high rating since I got it under the special introductory price, otherwise it may seem a bit expensive, but for many it will still be worth it.