data-attribute or Class selector

[simurai]

How do you prefer to author your markup when adding a new filter?

<div class="MyClass" data-filter="Eureka"></div>

or

<div class="MyClass filter-Eureka"></div>

I'm thinking of using data-filter mostly because: Filters can't be mixed together and only one at the time is allowed. data-filter="Eureka Karl" wouldn't work.