All of the above used the same OS, and all were competing on price. Sony did try to distinguish themselves in the design department, but they couldn't match the Apple design team. HP made some handsome machines, but once booted, they looked like everyone else.
They were all Microsoft's bitch, and though it gave an advantage in some markets, they had no control of the quality of the OS. In the end, they were boring in design and use. Their products were associated with work. Booting up your home computer shouldn't remind you of the crushing boredom of your beige box in your cubicle.