Selecting the correct LED product can be tricky as there are, yet, no standards to compare them to incandescent bulbs. Some say that LEDs are unique and a direct comparison is not possible. Stay tuned.
Unlike standard lamps LEDs are directional. So the viewing angle is important when selecting a product.
For example: the 1157 (dual brightness) bulb that is very common and the #1157 is a recognized standard product made by many Companies. The only difference being the quality.
When viewed as a taillight the angle is likley 100* or less. The lens helps to focus the light.
When we try to compare an 1157 to an LED we find a number of added parameters to be considered. www.superbrightleds.com
sells a varied selection that are claimed to be 1157s. But the only similarity is the socket configuration.
When it comes to LEDs we are in the transition period. We may as well keep track of the progress because it's a moving target.