There are too many if's and but to the complete answer than simple yes and no.
If your car is German or European brand, better stick to dealer than outside. In Japanese, Korean and American cars they are very simple and it's ok to get service outside after the warranty.
If you like to get more resale value then go with dealer to show the full service history record. This def pays 5-10% extra while selling.
If your car is specialize/modified sports car then stick to specialized garage and not the dealers, they will do more bad than any good. Performance garage have more experience in such cars.
If your dealer is reasonably priced, then yes. As many expensive brand dealer (not al futtaim) is highly overpriced here (too many to name).
If you don't know much about cars and don't want to know (ignorant or busy folks), then stick to dealers.