I did some side by side comparisons with the Ridged seesnake and the HF unit. There is a marked difference between them. The Seesnake was far clearer and had better depth of field. The Ridged was far better than the sub $300 fiber optic scope as well.
Take care as there is more than one model and only the 9.5mm head will fit in a spark plug hole. There is a previous version that does not have the controls right under the screen and a larger head. This version was being sold off in home stores such as Home Depot a while back. I did not have as clear an image as the later unit with the 9.5mm head. You can add extensions in 6 foot increments up to 30 feet and there is provision for connection to a recorder or larger monitor. I added a white line from the head along the cable to the handle. This lets me keep up and right and left lined up. The camera is not self leveling and as you bend the cable it can get turned from level. The line lets me keep things lined up as I feed it into a wall or other long penetration.
Amazon.com: Ridgid 31123 SeeSnake Micro 9.5mm Inspection Camera: Home Improvement