All depends on what you want out of it.  The new one is a single light intensity and uses 4 batteries.  No electronics.  Quite rugged.
The photon uses 1 battery and has multiple brightness levels and signalling settings.  Also includes hat clip and neck lanyard.
Get both!  LOL!  I think both have a place.
Not sure that the number of batteries is important, but just to get the facts correct, the white LED Photons have two CR-2016 batteries. 
More to the point, the PICO™ Lite has alkaline batteries and the Photon has Lithium.  That does make a difference in some regards, both positive and negative, depending upon how you look at it.
The switching is a key difference.
It should also be noted that the PICO™ Lite (at expected street pricing) is less than half the cost of the Photon.
I do agree with your suggestion, get both! <g>