In the recent past, intervention-class autonomous underwater vehicles (AUVs) have gained the ocean/marine research community's attention due to their multidisciplinary operational capabilities. This article discusses a detailed comparative-performance study of an underwater vehicle (UV) with two different actuator configurations based on fixed-thrusters and vectored thrusters. The fixed-thruster configuration consists of eight thrusters. Four thrusters generate thrust in the horizontal plane and the remaining thrusters produce thrust in heave direction. The vectored thruster configuration has four thrusters placed at diagonal corners of a rectangular vehicle, and four independent internal servomotors rotate these thrusters. The classification terminology in this article identifies the underwater vehicle without vectoring capability as Fixed-Thruster Underwater Vehicle (FTUV) and the one with vectoring capability as Vectored-Thruster Underwater Vehicle (VTUV). Furthermore, a nonlinear controller is designed, based on a backstepping scheme for tracking a given spatial profile in a three-dimensional space. An underwater robot's control for a trajectory tracking problem is useful for any real-time multidisciplinary autonomous applications. The comparative simulation results are summarized to validate both the vehicle variants’ performance differences. © 2021 Elsevier Ltd