Yes - etimers (stands for entity timers) are only visible to the specific entity calling it. timers, or global timers, are visible to every entity.
You choice of timer depends what you're trying to achieve.
etimerstart - starts/resets the specific entities timer, use this if only the specific entity reacts the etimer conditions (enemy stuck, adds heath for X seconds, etc.).
timerstart - starts/resets the global timer, use this is a number of entities react to the timer conditions (release enemies, spawn objects, etc.).
[url="http://raptr.com/No_Turn_Right?src=em_forum"]
[/url]