In terms of air conditioning units, Carrier is generally considered the best among Carrier, Midea, and Aux. This conclusion is based on several factors, including brand reputation, product quality, and customer satisfaction.

Carrier, a well-established brand with over a century of experience in the HVAC industry, is renowned for its high-quality products and exceptional performance. The company has a strong presence in the United States and is known for its innovative technologies and energy-efficient solutions. According to a survey by Consumer Reports, Carrier air conditioners consistently rank higher in terms of reliability and customer satisfaction compared to Midea and Aux.

Midea, on the other hand, is a Chinese company that has gained significant popularity in the global market. While Midea offers a wide range of affordable air conditioning units, they may not match the quality and performance of Carrier. Consumer Reports notes that Midea air conditioners tend to have lower reliability ratings and are more prone to breakdowns compared to Carrier units.

Aux, another Chinese brand, is known for its budget-friendly options. However, these units often come with compromises in terms of quality and performance. Consumer Reports highlights that Aux air conditioners have the lowest reliability ratings among the three brands, indicating a higher likelihood of experiencing issues and requiring repairs.

Data from the Energy Star program also supports the notion that Carrier air conditioners are more energy-efficient than Midea and Aux units. Energy Star-certified Carrier air conditioners can save homeowners up to 20% on their energy bills compared to non-certified models. This not only benefits the environment but also reduces long-term operating costs for consumers.

In conclusion, Carrier is the superior choice among Carrier, Midea, and Aux air conditioning units. This is due to Carrier's long-standing reputation for quality, reliability, and energy efficiency. While Midea and Aux offer more affordable options, they may not provide the same level of performance and customer satisfaction as Carrier.