Software-as-a-service (SaaS) is now mainstream; nearly all enterprises use at least some SaaS. But SaaS momentum varies widely by the type of application due to factors such as solution availability and maturity, business value potential, and inertia resulting from organizations' existing technical debt. This report analyzes the maturity, adoption, and potential for business value of SaaS delivery models in key categories of enterprise applications to help application development and delivery (AD&D) professionals plan their enterprise application road map.This report replaces previous versions of our analysis conducted in 2009, 2011, and 2014.