Hopper has received overwhelmingly negative feedback from users, primarily due to poor customer service and refund issues. Many users report difficulties in obtaining refunds for canceled bookings and express frustration with the app's support system, which often redirects them without resolution. Some users have experienced bait-and-switch tactics, where the booked accommodations were not as advertised. Despite its potential for predicting travel prices, the app's booking reliability and customer support are major concerns, leading many to advise against using Hopper for travel arrangements.