Really hard to say, as my experience with this has only been for a few months. May need some time to go through this, but so far, there hasn't been any truly big pain points, as I'm working within a startup and the inevitable fact of utilizing our resources to the bone :)
We needed a way to track updates to the website, social media, content and other deliverables for our product. With a small team that is bootstrapping the idea, we wanted to use a program that was going to be there long term, but at the same time was flexible enough to grow with us as we grew with the program. It's nothing like investing months into a program to realize that it dosen't fit anyone's needs anymore, or that the company shut its doors becuase they weren't able to secure future funding :(
Fortunately, with this product, not only could we grow with the free user base, but we also saw an opportunity that this wouldn't be taken away from us due to their low cost of more detailed benefits each month. As long as it didn't break the bank with us, we would be fine and honestly, with this product, it's really helped our idea validation as well as our bottom line :)
This program is perfect for small to medium sized teams who want to track multiple tasks and keep people updated in an easy to use interface, with attachments and other notes to make sure our productivity stays efficient.