If you are thinking of getting one or the other, I would skip both for one with the current generation LEDs. Doulble the output(Or more) for the same runtime, double the runtime for the same output or somewhere in-between.
If I had to pick between either I would go for the Riverrock because I like clickies(Then I would immediately try to swap the Luxeon For a Seoul P4 U-bin for double the output).