In principle I am not a fan of speedlights. Maybe it's because I've never been in touch with the right material. But for my taste most speedlight images are either totally flat or have a massive light-falloff between the object and the background. At least they completely change the mood given from natural illimunation which is exactly what I prefer to capture. But this is of course a preference of personal taste.
No depth at all.
Whitebalance direct sun
A little too cold for me.
Whitebalance cloudy sky
A bit red, perfect for rust.
Another thing of personal taste is the color tone. I do prefer more saturated colors, so I already pushed saturation within the camera. If it's too much, it's easy to reduce later.
When talking about colors, we have to mention whitebalance. As you'd probably guess, I don't like automatic whitebalance and choose one of the presets most time. Under a clear sky in Europe I prefer "cloudy sky", which results in a warm tone. Using a fixed whitebalance ensures that all images of a sequence will have a homogeneous tone.
Under artifical illumination I always do a manual whitebalance for optimal results. You can do this with a pricey grey-card or a cheap white (unused) handkerchief. This gives much better results under (homogeneous) mixed light, as any one of the presets.