colwiz

First and foremost - how common is it to find a free solution that is not underdeveloped? Well, colwiz is absolutely free tool which will probably get your attention but what's even better, it suits for both desktop and mobile, allowing you to view your entire library on the go. At the same time it is cloud-based as well - the flexibility it has is crazy!

When talking about a free software, there is really nothing to dislike. Even if I'd really like to pinpoint something, I couldn't as I find it being one of the most straightforward solutions - share your content, annotate pdf's, add references - whatever is your goal, it is extremely easy and handy tool!

It is likely one of the best solutions for students and researchers who are looking for immense capability without a price tag that would break the budget. Easy interface and flexible usability take it a notch further than with any other software and it even adapts to all operating systems so there is really not a single reason why not to try it out!