In general terms, if the manufacturer sees fit to use a particular component type or recommend a particular component, I see no reason to change it, unless your seeking to IMPROVE the bike (or car for that matter) to suit your riding style or budget. For instance, tyres, front forks, rear shock, brake pads or brakes etc. But IMHO why muck around with something that works....
Obviously the above relates to new or near new in good condition, not old bikes that NEED work done to them.