You can almost flip a coin between the SF and CB since their main LED is the same wattage. Due to their different optics, the Cherry Bomb gets a little better dispersion side-to-side, but the Superflash gets good distance.

Whichever one you get, mount it on the bike and aim it level to the rear so that it doesn't point at the sky or the ground. You could afford to point it a little to the side to hit drivers better, but don't go so far that you lose rearward visibility; use a wall when aiming to make sure that you still get plenty of light directly along the bike's centerline.