EagleTac D25A2, New Vs. Old mode, U2 Vs. U3?

Working on a friends car I lost my favorite EDC light, my EagleTac D25A2 Clicky.

I see no reason not to get another one but I see they have a newer model now. The D25A2 Tactical.

Looks like they discontined the older model but I am seeing some dealers listing them still with the mention of them being "upgraded" to the newer, brighter LED's that are 470+ lumens.

So that said, I see it listed at two different models.

I see one listed has having a CREE XM-L2 U2 and a CREE XM-L2 U3... What is the difference between the U2 and the U3?

Also for those of you who have seen both the older D25A2 Clicky and the D25A2 Tactical in person, the Tactical model looks bigger. Looks bigger in diameter and length. Can anyone confirm?

For reference I've provided some pictures. I had the model on the bottom.

Typically/generally speaking U2 to U3, that is the "bin" of the led and the higher number is typically a small percentage brighter, estimate around 5-7%. Which is almost not noticeable. There can be other minor differences, but I won't go that deep.

Edit: found this for you:
http://flashlightwiki.com/Brightness_Bins

They are replacing the clicky with the new tactical model. I have been in contact with illuminationGear,com for the past week about it and they have special ordered me a nw xml2 as I love the clicky user interface the best. Here are links to the technical spec pages on Eagletac's website for each of the lights:

Clicky
http://eagletac.com/html/d25a2rc/specs.html

Tactical
http://eagletac.com/html/d25a2tac/specs.html

The user interface is completely different between the lights, instead of using the switch to change modes, everything on the tactical is done by twisting the head. If you really liked the clicky I would recommend going ahead and getting another while you can