Graphene nanoribbon FETs (GNRFETs) have emerged as a promising candidate for nanoelectronics applications. This paper summarizes (i) current understanding and prospects for GNRFETs as ultimately scaled, ideal ballistic transistors, (ii) physics-based modeling of GNRFETs to support circuit design and CAD, and (iii) variability and defects in GNRs and their impact on GNRFET circuit performance and reliability.