EFM
EFM is more resilient, this allows it to ride out some failures and it doesn't suffer from contention at peak times because you're not sharing the link with others on the same exchange. Ethernet first mile is now enabled on many Openreach exchanges across the country, making it available to around 80% of businesses in the UK.
EFM uses the national fibre optic networks to provide internet services however the final delivery method differs as there is no requirement to bring fibre optic cable into the end premises. The last mile is delivered using copper circuits from the nearest serving telephone exchange.