Zebralight produce 1AA headlamps with three different beam profiles.
The H502 has a wide (~80 deg) even beam profile, achieved through the use of a lens. This is good for task or area flood lighting (think like a streetlight). So the H502 is good for stirring your pot, reading, hanging up over a table for playing cards, tasks that are within arms reach. What it is not good for is viewing objects far off.
The H52 has a reflector to provide a more focused beam profile with a smallish brighter area in the middle of the beam surrounded by a wider cone to provide some spill (think car headlight). This type of beam is best for walking at night. It is okay for task lighting but some people find they have to move their head around a lot more to light an whole area, which can be distracting.
A third model is the H52F, which has a diffusion film over the front glass to blur the more focussed beam into a wider softer beam, again with some spill. It's sort of a blend of the first two models. Depending on your point of view, it either provides a good blend of light for tasks and walking, or it is a jack of all trade but master at none.
My personal preference is for the H52 beam profile, given most trips I do involve anywhere between 2-4 hours of walking on rough tracks on a Friday night to get to the first campsite/hut. For task lighting you can use a lower level.
Zebralight also produce the same models above with different tints of white leds. The models above are all cool white leds with a colour temperature of about 5500K (think cool white flouroescent tubes).
The second type are called neutral white leds and Zebralight give these models a W suffix so e.g. H52W, H52FW, H502W.
Cool leds are more efficient than neutral or warm white leds generally (although the gap is reducing) so produce more light for a given current level from the battery. Because of their increased blue light component they can appear brighter than a neutral white at the same light output. However their downside include a reduced colour rendition (i.e. colours appear less true compared with sunlight) and cool white leds tend to reflect back light when encountering mist or fog, making it harder to see.
Neutral white leds are less efficient (but still pretty good) but their colour temperature (4400K) and colour rendition (~75CRI) are closer to that of sunlight so colours appear more natural. Also they don't suffer as badly in mist or fog as cool white leds do.
There "sunlight" leds available (not in Zebralight headlamps) that have better colour temperature and rendition than neutral white leds, but at the cost of further reduced efficiency again.
I currently use a H51W (the previous model of the H52W) and would happily upgrade to a H52W.