to come back to AA vs Lithium discussion:
I have 2 ProX
initialy without extender.
Very frustrating because most of the time with 2 subsequent shots, the second one was not lighted.
I added battery extenders ($$$), and issue was no longer there, but
-good, but not exceptional recycle time.
-with the cost of higher overall length (not critical)
-more manipulation with a total of 8 O-ring. With some time to time difficulties to insert extenders.
-many batteries. 2 sets of 16 AA (because in some situations you don't have time of possibility to recharge, especially with 3 dives per day.
With lithium batteries, I expect
-better capacity : it sems ok. Enough for 3 dives ?
-bette recycle time : not sure how it compares to Pro X...