Am an Xamarin Developer , I used to use Sqlite as mobile database ,
recently Realm comes to the picture.
Any idea about Differences between them in
Performance & ease of use..etc?
What is the best practice of using either one?
Realm and Sqlite are quite different in many aspects.
Here are two articles you could go through to grasp the main differences:
System Properties Comparison Realm vs. SQLite
5 Reasons Why You Should Choose Realm Over CoreData/SQLite
As suggested by Slavia in the comments, take also a look to this article for a comparison of several ORMs, including Realm.