There really isn’t much to say about them, or any kind of brand. Get something that’s only a few dollars and in the 15ish or so Watt range. I know one of our top modders, Gummowned, uses a regular RadioShack brand soldering iron. You can use higher wattages if you want, they just generate more heat than lower wattages. However, when starting out, it’s better to start with lower temperatures to make it work more slowly while you practice.
Bottom line is, The only point of the iron is to generate heat into a tip. Get something with a fine tip, with the right amount of power (which may take some experimenting. I like 30W, but I’m thinking of getting something with a bit more power)
Only thing that you should spend a lot of money on is a soldering station, then you may actually want to look for a specific brand or attributes.