John Hansen wrote a review of Petzl Tikka XP 2 Headlamp on November 11, 2012
Familiarity: I've put it through the wringer
Was happy with Tikka 2, but wanted more light. This XP2 met my needs with a big plus -- designed to accept lithium batteries. In the winter, lithium is key and the Tika 2 was not designed to use lithium batteries. It works well in lots of water (used it during a rescue with 6+ inches of rain in 4 hours). Have used it down to 20 degrees with regular batteries. Expect to use it in colder temps this winter.