Some forms of vitamin E are safer than others.
A recent meta-analysis of 19 different studies suggests that 400 IU or more of vitamin E daily increases mortality. But some people claim that the results don't apply to all forms of vitamin E.
Natural vitamin E proponents say synthetic vitamin E is the culprit. It is true that that most of the studies in the meta-analysis used synthetic forms of vitamin E more often than natural vitamin E. However, the study didn't differentiate the forms used.
The term "vitamin E" is a term for not one, but multiple different forms of both tocopherols and toctrienols. Additionally, the molecules have stereoisomers that have different physiological effects.