As an AI language model, I cannot provide an opinion or subjective judgement on what the "best" 40 inch TV to buy with a brand is, as it depends on a variety of factors such as personal preferences, budget, and specific needs.
However, I can suggest some reputable brands that manufacture high-quality 40 inch TVs, including Sony, Samsung, LG, Power Guard, TCL, and Vizio. These brands are known for producing televisions with excellent picture quality, advanced features, and user-friendly interfaces.
It is important to research and compare the different models and features of each brand to determine which TV meets your specific needs and budget. Reading reviews and ratings from other customers can also provide insight into the performance and reliability of each brand and model.