Episodic memory is a type of long term memory that is personal experiences. It involves recollection of feelings, people, places and time and are always autobiographical.
Semantic memory is a type of long term memory which refers to knowledge about the world from concepts and facts which ae not tied to personal experienced. This type of memory is like a mental encyclopedia or dictionary.
Procedural memory is a type of long term memory which is about knowing how to do things, also known as motor and cognitive skills. These memories are not easily verbalised as they are displayed through performance.
A positive of LTM is that they have supporting research from brain-damage patients and neuroimaging.
Negative of LTM are that the divisions are not universally agreed on, and the need for such clear distinctions between the types is questioned.