When should I use OMT instead of UML- class diagram in practice?

Although I found an article about OMTvs. UML I can't figure out the consequences of using OMT instead of UML- class diagram. What are the benefits of OMT compared to UML- class diagram? As far I know I can depict a class diagram in nearly the same way than this is done by using UML, or are there any known circumstances where only OMT is able to illustrate a specific context? And a bit more interesting question is, what are the criteria used to select between the two modeling tools?