Recommended SQL server service accounts In my SQL environments most of the SQL server are running under '.\Local User' with Power user groups rights and some sql servers are running under virtual accounts 'NT Service\MSSQLSERVER'.

I know its best to run SQL service  under Domain accounts, but I need to know best compared  to Local User '.\Local User' vs Vertual account 'NT Service\MSSQLSERVER'.
The MSDN Page Configure Windows Service Accounts and Permissions has some detailed recommendations for the SQL Server 2014 service accounts.

The subheading for configuring the services is at Service Permissions

This is quite a detailed outline of recommendations for the SQL Server Service Accounts.  These are good recommendations, however you can make your own decisions on configuration, based on your needs for security and for being able to manage the configuration.

Truth in reading: Although we use many of these settings, we also have some variations that suit us.