The short answer is that while a cheaper unit might work initially, the difference in longevity and smooth operation comes down to the build quality of the core components, specifically the rails and the motor assembly itself. You aren't just paying for the brand name. And often, the price difference you are seeing between a big box store budget option and a higher-end model reflects diffrent levels of component quality.
When you are dealing with a heavy solid door, you need solid rails, not just extruded aluminum pieces that require extra fasteners. Those high-end models use construction designed to handle more torque and less vibration over years of use. The budget units often cut corners on this, leading to increased deflection and noisier operation down the line. It's definitly more than just opening a door; it's about the smooth, quiet feel of the mechanism every single time you use it.
If you want the best expirience, bypass the rails entirely. Look specifically at models designed for a wall mount or jackshaft setup. Those units are built differently and eliminate the mechanical issues associated with traversing a rail system. It keeps the whole mechanism compact and often gives you better power handling for heavy doors without the rail issues.
Regarding the installer, be extremely wary of free install offers. Those guys often pocket the labor cost and you lose the ability to leverage the warranty if something goes sideways. You want a profesional install that doesn't create future liability issues for you. Focus on the rail construction and the mounting type; that is where the real value is found.