I would like to have some index indicating how well the grid node server performs related to other servers.
For instance, if I run 2 grid servers on Azure and 2 on internal network, I want to know if it's worth adding more servers on Azure or on internal network (or if it helps out scaling Azure servers etc.).

One idea might be to have an average processing time on tests, and check when test has been executed on different servers is above or below the average execution time and calculate some sort of performance index from those measurements and e.g. display it as a column in the "NCrunch distributed Processing" window.

See also https://ncrunch.uservoice.com/forums/245203-feature-requests/suggestions/5663837-make-ncrunch-grid-performance-measurable (which is about programmatic access to performance details)