CAT, Deere, Komatsu, Volvo, or Other

So I'm working on a research product on the service/support offerings customers receive from the dealerships where they purchase products as well as on customers experiences with particular products. So what I was looking answers on are... What have your experience been as a customer when dealing with a dealership pre purchase, during the purchase, and post purchase? What maintains your loyalty to one brand or product over others? Is there one name you prefer over another, if so which name and why? How is the customer relationship treated throughout the lifetime of the product? Which company has provided you with the most reliable products? What sort of services and support do you wish your product had that you have seen other companies offer their product? Answers to any of these questions would be extremely helpful. Thanks!