What is difference between end event and a terminate the event?

I always recommend that a process have a terminate event. A terminate event makes sure that receive email message nodes are no longer listening, timers are no longer active, quick tasks (for process backed records) are no longer available, ... This will make sure that this instance of the process model is now beginning its data management journey to archive, that in turn, helps keep your environment leaner.

Strong agree -  I make all end nodes Terminate nodes until/unless otherwise required.  In fact I'm actively annoyed that there's no way to add terminate nodes by default or at least have them show up as an extra selection - since it costs 5 or 6 clicks to switch an End around and activate the Terminate functionality.

Agreed. 

If Appian is still interested in time savings, just look at the total minutes recovered across an application's development when you've made Terminate the default behavior of the node, and End the secondary behavior that you have to explicitly define.

Agreed. 

If Appian is still interested in time savings, just look at the total minutes recovered across an application's development when you've made Terminate the default behavior of the node, and End the secondary behavior that you have to explicitly define.