The advertising blurb often uses words like "high bright" "super bright" or makes a big deal of the number of LED's.
None of this tells you how bright the light will be.
When you buy a lamp we are used to choosing a "40W" bulb or perhaps a "100W" bulb if we need good light for fine work. We look for a NUMBER that gives a clear idea of how bright the light will be. Choosing the newer "low energy" lamps (compact fluorescent CFL) the box tells us "40W equivalent".
The number that tells us how bright a light is is the LUMENS.
Tungsten Lamp Energy saving CFL Light Output(Lumens)
25W 5-6W 220 – 300
40W 8-11W 400 – 550
60W 13-18W 850 – 1160
100W 20-25W 1200- 1750
When you are choosing LED lamps you should do the same. Generally, a good LED lamp produces around 100 Lumens per watt; so to replace a 40W tungsten bulb you need a 4W LED lamp.