This document provides an overview of the pros and cons of challenging patent validity in the Patent Trial and Appeal Board (PTAB) versus district courts under the America Invents Act (AIA). It discusses the various post-grant review procedures available at the PTAB, including inter partes review, post-grant review, and covered business method patent review. Statistics on filing and outcome rates for AIA trials are presented. Factors to consider when deciding between the PTAB and district courts for a validity challenge are outlined, such as the nature of the decision maker, evidentiary standards, discovery opportunities, costs, and timing.