I think it really depends on how much elevation change you want. I have some grades on the lower level of my layout, and the benchwork is open grid. I'm sort of wishing that I had done straight decking, because now I'm going back and filling in the holes. When I built my upper deck, everything is flat, so solid deck was a no-brainer.
These are old photos, but you can see the holes I'm talking about. Some have been filled in already.