That makes sense! Unfortunately, it'll be hard to obtain benchmarks for every plan with every provider, and it'll be even harder to get enough benchmarks with each provider to paint an accurate picture.
Even with the same provider, there can be massive differences between VPSs, it just depends whether you end up on an idle host node with no noisy neighbors or one where everyone is busy mining their favorite cryptocurrency.
Regardless, we do understand the need for accurate performance numbers, so this is something we will explore further in the near future.
If you have any ideas, please let me know. :)