When I install a system, I don't install parts from only one manufacturer. I design a system to be installed for a client that meet the watering needs for that client. That might mean a system being made up of; Rainbird 5000 series rotators, Toro valves, Hunter pop-ups and MP Rotators as a spray head, a Nelson/Signature controller, and shrubblers for the drip/micro zone(s).
What it boils down to is that different contractors like different product for different reasons. You haven't told us your watering requirements/needs, sun/shade conditions, turf area, garden area, etc. You could have a football field, six acre property, or a 20'x40' inner city sized turf area to water. Different needs, different manufacturers, different heads, different valves and so on.
Mick
Irrigation Contractor
Certified Backflow Assembly Tester