A mismatch between user-technology usage and a lack of user acceptance hinders the adoption and diffusion of technology. In this research paper, we focus on the differences in how mixed reality (MR) and augmented reality (AR) impact user adoption. We also examine the importance of user intentions in relation to MR and AR for purchase behaviour. A survey (n = 801) was conducted in the UK in May 2022 to investigate the relationship between AR and MR technologies and compare their compatibility for various intentions, including intent to use (9 factors), intent to experience (7 factors), and intent to purchase (7 factors). The results indicate that MR shows more promise than AR in the retail industry. MR significantly and positively affected five elements, such as shopping, while AR was primarily used for gaming. This study provides practical insights that can aid in technology adoption and evaluation. It also emphasises the importance and feasibility of incorporating product customisation functionality into MR retail purchase applications, which has inspired our subsequent development of the MR user interface.