How to get local Time of user depending on his Country in ASP.Net

Lets suppose my application is deployed on a server located in USA. Now if any client visits my website from anywhere and from any device e.g Mobile , iPad , Surface or Laptop. Now if i want to save his local time then what should i use ?

DateTime.Now;

or

TimeZone curTimeZone = TimeZone.CurrentTimeZone;
var yourTime = TimeZoneInfo.ConvertTime(DateTime.Now, TimeZoneInfo.Local, TimeZoneInfo.FindSystemTimeZoneById(curTimeZone.StandardName));

Also please tell me the difference between both commands.