To keep up with the maintenance demands of a dynamic fleet of equipment, military personnel are constantly learning new repair skills. However, this constant training can be time consuming and cost prohibitive. In fact, United States Military spending on operation and maintenance equaled $200 billion in 2015. One method of reducing these costs is to employ more efficient methods of delivering work instructions, such as Augmented Reality (AR). Studies on the use of AR work instructions have shown reductions in task duration and errors by as much as 50%. Although previous research has confirmed the advantages of AR over traditional 2D work instructions, little research has been conducted to evaluate the advantages of emerging AR hardware, such as the Microsoft HoloLens for delivering maintenance and assembly information. This paper presents the results of a comprehensive user study comparing four work instruction delivery methods. Users were asked to perform a mock wing assembly task with work instructions using one of 4 methods: 2D instructions on a desktop computer, 2D tablet instructions, AR tablet instructions, and AR instructions on the Microsoft HoloLens head-mounted display (HMD). Results of the study showed that viewing the AR instructions using the HMD yielded faster assembly times than the other three instructional methods. The study also showed that users made very few errors when using AR methods in general. However, net promoter scores (a measure of user satisfaction) and qualitative feedback from the users showed that some improvements in comfort and 3D registration may be necessary before the HoloLens can be successfully employed for widespread military maintenance use. Despite this subjective feedback, the HoloLens HMD has the potential to provide warfighters with quick access to work instructions that will decrease the need for expert assisted training and increase readiness of military equipment.