There are several debates over which type of lighting is better between natural light and off-camera flash lighting. Some photographers build their style on one over the other, while some find themselves using both. I believe that it comes down to your personal preference in which you like over the other.
To help you make your decision, Manny Ortiz shoots a few portraits with his model wife to compare both lighting scenarios. The first shot in each set is only using natural light during golden hour, then he changes the exposure for the background only and used the eVOLV 200 TTL pocket flash paired with the 38-inch Glow ParaPop softbox to add some fill light for the model. You can compare the shots below to see which one you prefer over the other.
Directly following the shooting examples, Ortiz goes into the pros and cons of each type of lighting situations. I would like to reiterate, with the misconception of natural light being easier than off-camera lighting, I agree with Ortiz on this one. I guess it depends on how you look at it, set-up is easier but actually shooting in the sun isn’t easier than shooting with strobes, as the sun and the sky are constantly changing, which can force you to adapter your settings and possible setup based on how it is at that given moment. Another minute later and you might have to completely change everything again which can happen multiple times throughout the entire shoot. With off-camera lighting, it may take a bit longer to set up, but once you have everything ready to go, you can just keep shooting until the set is done.
From the examples shown by Ortiz, I personally prefer the portraits utilizing off-camera lighting. However, I can’t tell you which one is better as I use both types of lighting and I believe it comes down to your preference and style. Recently I went through my personal photos to select some of my favorites and two of them were shot using natural light and one was with off-camera lighting. I do suggest you learn both methods and use the right lighting based on your situation, understanding lighting and being prepared can save the shoot if the scenario changes, but it all depends on what the shoot is for. Which lighting style did you like better from Ortiz's shoot and which do you use?
Images used with permission of Manny Ortiz.