The E2e with the stock bulb will blow the KL3 out of the water.
No comparison at all.
Were you perhaps asking about the E2e with a KL1 versus the KL3?
If so then that's a bit different.
The KL3 can run on either 6V or 9V and is made to fit the 1" body SureFires (6P, 6Z, C2, D2, Z2, 9P, 9Z, C3, D3, Z3).
With the 6V its nearly identical to the KL1 (also on 6V).
They do use the same LED after all.
The KL3 with 9V is supposedly brighter than the KL1 but still not by that much.
I also keep hearing the KL1 being compared to the X5T.
Well I finally got to compare the two recently and the KL1 is the clear winner in my book.
More light and MUCH more throw. The throw is the key difference.
The X5T may be a decent task light but the KL1 can truly be considered a flashlight.