One of the most useful features of Eloqua is the ability to build groupings of filters that you can use over and over in segmentations. You can even modify them, and any segmentations that use them will automatically update to use the new logic. It’s a pretty elegant way to help users leverage common filter logic without needing to remember every last item, and certainly to avoid the issues caused by missing a critical filter.
Of course in Marketo, you can do this with dedicated smart lists, or even segmentations to accomplish a similar effect, but it’s nice to have a purpose-built feature for this sort of thing. A trend I’m seeing a lot with Eloqua functionality.