I don't really understand all the negative stars. I've been using inkFrog open since almost the start and it has been very stable for me and saves me a huge amount of time. I recently tried to switch to Vendio since I wanted to try some multi platform selling - and their system was so buggy in comparison. It was such a huge waste of time that I have never experienced with Inkfrog.
I suspect people stop appreciating what they have until they lose it, like I did.
Anyways I can't recommend Inkfrog Open enough after that experience.