If exact appearance of your geraniums does not matter, use the cascading! The upright (Zonal) geraniums are much more prone to catipillars and fungus, especially rust which appears on the underside of the leaves.
At the places in Malibu that I have put in geraniums, the cascading look great, tend to need less care, and, because they are healthier, help your other plants stay healthy as well.