There is a huge difference. The screw bulbs are almost always spiral in shape. This leads to a huge loss of light due to re-strike. Also due to the design of the bulb and the high amount of re-strike getting any kind of decent reflector is almost impossible. With the screw type bulbs I figure that you get at most 40% efficiency of the bulb.
With the straight pin type you have much less re-strike. Also the bulb is longer which gives better coverage. A simple white painted reflector will work fairly well with this type of bulb.
With the straight pin type you have much less re-strike. Also the bulb is longer which gives better coverage. A simple white painted reflector will work fairly well with this type of bulb.