Here's a mini review of the Petzl e+Lite emergency head torch/headlamp which I got not long ago. It is the original 2008 model without the whistle, but otherwise is exactly the same as the newer slightly more expensive Petzl e+Lite 'plus'. This isn't my primary head torch (well except in the summer) and instead is left in my rucksack as my emergency torch for times when I am without my primary head torch or when it fails.
The e+Lite is bundled with a translucent red case, designed to be waterproof up to a metre. There are five modes, all toggled via a handy dial switch on the front: economy - perfect for stumbling around the tent looking for keys, maximum mode - which is capable of creating a light beam up to 19m, flashing mode - self explanatory, red flashing mode - also self explanatory, and finally red beam - for when preserving night vision, this is an excellent mode for map reading when stumbling across in the dark.
Here it is next to my already diminutive but heavy Petzl Zipka headlamp with integrated headband. The e+Lite has three main white LEDs and one red LED. The switch can be 'locked' as well to prevent it from accidentally turning on. It is powered by two CR 2032 batteries, which can be bought at any good watch shop. The batteries are good to last up to 45 hours in economy mode or 35 hours in maximum mode.
Another shot comparing the size to the Zipka. The e+Lite is slimmer and the joint allows me to control the direction of the beam (the same can't be said about the Zipka). The headband can be removed allowing me to use the built-in clip to clip it onto my cap or jacket - making it even more portable and useful.
The e+Lite comes with 10 year guarantee. Is it a suitable proper head torch replacement? Depends. In the summer months and for walking from the campsite to the pub the e+Lite works perfectly as a head torch substitute. I wouldn't recommend using it as a primary head torch when walking in the fells though.