Although a Lumen is a fairly accurate way of measuring the total output of a light, it can be misleading while choosing a light for your application. The Lumen measurement is based on the overall output of a light in all directions. That might be convenient when trying to light a room but when trying to light a work area, we are only concerned about the light shining on a specific area, preferably towards the work being performed and not towards our eyes. Therefore if you are comparing two lights with the same Lumen output, the one that directs the light where you want it is going to do a better job of lighting that area. This becomes particularly true when measuring LED lights. Since a fluorescent light by its nature sends light out in all directions it must use a reflector to redirect the light towards your work area.
An LED light on the other hand, only sends light out in a specific direction. The angle of the light being emitted depends on the particular LED being used. Older LED technology could only emit light in a rather narrow angle. As LED technology has improved, the angle of the light output has increased as well as the overall light output. With all the variables in play when using Lumens, a more useful way to compare lights is to look at the light output in the specific direction you need. That's why a better measure if light for this type of application is Foot Candle.
A Foot Candle is defined as "a unit of illuminance or illumination, equivalent to the illumination produced by a source of one candle at a distance of one foot and equal to one lumen incident per square foot". At least with this unit of measurement, you are measuring the light being emitted in a direction that matters but even that measurement has its downfalls. That's where Kelvin comes in. Kelvin is a measurement of the Color Temperature of a light. Without getting too technical, the higher the Kelvin, the whiter the light. This complicates the comparison even further since a whiter light will appear brighter to the eye than a lower Kelvin light when all other things are equal. When it comes right down to it, the best way to determine which light is best for you is to take each of these measurements into account.