There are two major approaches to purifying contaminated water: you can try to trap sediment and microorganisms via a filter, or you can use various methods to sterilize the water by killing anything living in it.For absolute safety, some recommend doing both, so I'm not going to sit and compare tablets to a pump filter, as they are different mechanisms of purification that aren't necessarily competitors. In fact, regardless of how you kill the bugs in your water, I recommend at the very least running the water through a cloth/bandana first as a first step in removing dirt and larger microorganisms.That gives these tablets three major competitors...The first, and cheapest, competitor is good old-fashioned boiling of water. In fact, boiling kills most things that some chemicals might not even get to. The downside, of course, is the need to start a fire, wait, and boil water. Good if you're camping overnight and prepping for the next day, but not so great if you need to fill up in the middle of a several-hour trek. If you're the kind of person who carries a mini-burner and a stove-top anyway, you probably don't need these tablets.The second, and most expensive, competitors are the UV light devices that sterilize using light. It sounds like nonsense, but it does in fact work. The problem is the cost and reliability. Sure, it can be argued that if you break down the cost per liter of water of a sterilizing pen is actually lower than using tablets, but that's only assuming that you actually get the maximum number of cycles that the manufacturer claims it is good for, and it ignores the cost of the batteries and the reliability of the products. From my experience (luckily, not with gear that I had to pay for), the SteriPEN is finicky from time to time. Unless you're doing light day-hikes, I wouldn't rely on batteries and electronics to hold up. Especially over years of hard use and being banged around in a backpack. It's nice having neat technology to show off, but nobody will be impressed when your magic light is broken and you're crapping your pants (literally).The third source of competition is other tablets/drops. There are several types, and while some tout better flavor, more effectiveness, etc, it really comes down to whether it'll kill the bugs in whatever area you're hiking. In other words: most of them are the same unless you're headed to an area with a very specific rare microorganism that certain tablets won't kill. These have held up for me through years of trekking on four different continents. That's quite good enough for me. The taste, sure, is a bit off, but it's nothing unbearable. Between tablets, I don't have much of a preference, but I do prefer tablets over liquid drops, as they're easier to carry and use.
