all designs (no matter what the product) are sets of compromises, with the choices made by the design engineers that they think will make their design best for the specs.
You can know that some brand's machines made since 2003/2004 have considerable (proprietary, trade secret, password protected) diagnostic and setup emissions related computerized controls, while other brands have avoided being quite as secret and protective of the information required to troubleshoot emissions related problems. Which brands are free with repair information may have as much to do with the local dealer's protocol and employees as it does with the manufacturer's policies, so you may find a "second choice" different between people in different locations.
I think a lot of techs will tell you the brands they are the most familiar with will be the ones they think are better, as this is just normal human nature.