I love the concept, but the implementation is too limited for my purposes.
There is 1 make or break feature for me:
1.) Integration with windows explorer & other file explorers: Being forced to use the Tabbles interface means that I can not use my existing workflow & preferred file manager (Total Commander in my case). Integrating the program features closely into windows, will be beneficial for the widescale adoption of the application, since it would be more likely that a lot of people would start using the program (and buy it of course).