[Mvandenbergh]

Earlier generations of Nest didn't have proportional control capability of any kind, no ability to apply Load or Temperature compensation either which are things that less polished looking heating and cooling control systems have been able to do for decades.

To be fair to Nest, newer versions are able to do this but many heating and cooling systems don't expose those functions on a standards compliant open way. As a result, a vast number of heating and cooling systems runs about 10% less efficiently than they should but there's really no way for end customers to know that since they don't have a reliable benchmark to compare against.