Introduction The user experience and clinical effectiveness with wearable global positioning system (GPS) devices for persons with dementia (PwDs) and caregivers (CGs) remain unclear although many are available. Methods Using a crossover design, 20 dyads tested two similar commercial GPS watches (products A and B) at home for 4 weeks each. Usability, product functions, design features and product satisfaction at home and the clinic were investigated. Caregiver burden and quality of life assessed clinical effectiveness. Results The final 17 dyads rated the usability, telephone function, overall design features, font, buttons, and battery life of B significantly better than A. PwDs rated the overall design features and buttons of A significantly better than CGs. Product satisfaction with both products was significantly lower at home. Clinical effectiveness was not found. Discussion User experience can be improved by optimizing specific product details. This might translate to clinical effectiveness. Social desirability bias may explain different product satisfaction ratings.