I was initially delighted by my Alpkit Gamma. Over a 2 year period this torch needed a new battery case (replaced no hassle by Alpkit) and then became increasingly temperamental - not turning on. The metal contacts in the battery compartment had corroded/dissolved away. I used the torch for walking the dog every evening in the winter and camping/hiking. I looked after it very carefully.
Therefore it is great value but if you use a torch a lot and/or need 100% reliability you may need to buy a spare. My experience with Petzl and Black Diamond is that they are a bit more expensive but are better made and last longer. My latest favourite is a Black Diamond which cost about £25 from Cotswold and is more powerful than the AK Gamma.