If you want to use the thing, just remember that 1 AA battery has a similar capacity to 3 AAA batteries.
That advertised runtime is usually off by a factor of 30 or so, because they often count the entire time you can see light coming from the LED, not the time that it is putting out useful light.
See if they are compatible with lithium disposables or Ni-mh, as many are not.
If they are regulated for brightness, they will typically not last as long on batteries as one that is unregulated, though sometimes they must be regulated, ie; single battery models.
See if they are waterproof, many are not.
Look at the switch type for your uses, the Petzl Tikka has a slide switch that won't come on accidently, but the PT (can't remember the model) is waterproof and Lithium compatible.
Personally, I don't worry about interface or which mode comes on first, or how much light it can put out, as I normally put it on my head on low at night, or high in the daytime, and leave it that way. If I need more light, I have a flashlight that is easier to adjust.
Battery life IS important. Ideally, you want to be able to go 8 hrs or so with good brightness. When I am working in less bright areas, I put mine on high, and it runs for 4-5 hrs on Eneloops, which is not too bad. On low, it is nice when you can just leave the light on whenever you need it, and go a couple days without worrying about battery changes, as they usually happen in the dark.
I have the midline Princeton Tec with the single LED, that is blue and says H2O 1M on the front, I can't remember the model. It is 50 Lumens, with good runtime, rechargeable and lithium compatible, has a fairly wide beam, is rugged and fairly light, and the switch isn't likely to get pushed on accidently. Though with difficulty, it can be operated with gloves on.
If I had to get another one, I would probably start looking at some of the new 4Sevens lights with a headband, for insane battery life, small size, and redundancy. Or just get another Princeton Tec light.