A traditional performance study typically reports on application performance. Moving to cloud environments that require developer time and accounting for costs, these other two dimensions must be considered. Here we present the Usability Rubix, a conceptual framework for investigating the choice of how to deploy an application. It shows that the choice to deploy a specific HPC application in a cloud comes down to a three dimensional trade-off with dimensions for cost, performance, and human effort. As an example, a large amount of developer time might be worth it for a lower hourly cost, and that decision might change further if the application is intended to be long running. A sub-optimal performance might be OK if it greatly reduces developer time, or leads to a lower cost. Any specific build of an application can be mapped into this space, where each cell is a specific combination (low, medium, or high) for each dimension.