Color Saturation and Hue: Colors are very saturated and hues are commensurate with HDR processing.
Brightness and contrast: The brightness is good. The contrast is a little harsh, as are most HDR processed images. Still it makes for an interesting effect.
Focus and depth of field: Focus is very nicely done. Depth of field is deep, which is appropriate for this image.
Subjective: Overall, a good image. However, the processing was a little over the top for most voters. The result was a little harsh on the eye. The processing brought out some really nice detail, but at the same time introduced artifacts such as the aura or glow around the right side of the engine. (I've had this happen using the Spicify setting in Topaz Adjust.) I like that you chose to include people in this image, it helps to give scale to the engine. I've seen this engine up close. Your effort is great on the detail of this mammoth beast. I'd like to see this redone with a little less harshness, and for a challenge such as this, a bit more grain. Voters can be very literal.
Someone thought this was mine, probably because I've photographed it myself when it was in town. I'm not really seeing any grain in it, I'm afraid. I'm sure it has some at full size, but it doesn't appear to have survived the downsize to 800 pixels. Some bad fringing on the right edge of the engine as well. I'm sure I'm not the first to mention that and you're probably getting tired of hearing it.