It breaks down to what you plan to do with it. Are you going to need to field charge off of a battery or solar? If so, you want DC capabilities. Many people ONLY want to charge at the field and don't want to charge at home, so they cut out the AC to try to save money. I'm of the mindset that you get something that does both.
Others will tell you to just buy the absolute cheapest chargers, because you're trying to save money. On this, I disagree. My dad bought a cheap Tenergy charger from HobbyKing, and he's started having problems with it. It DOES charge, but the buttons to switch between battery programs have stopped working, so he has to constantly cycle through on the one button that DOES work to get from a 2S to a 3S or 4S, and between storage or flight charge. It's kind of a pain. Also, while it's flat, it's kinda big for what it is; he ends up carrying it in a grocery sack when he goes to the field to fly, along with his transmitter.
There are two things you want to be quality, and I'm sure some people will disagree that it's needed:
1) Transmitter
2) Charger
These two things, I will tell you to find what fits YOUR needs, and spend what gets you the most bang for your buck. With regards to chargers, if you're having to change it out every 6 months for the same model because the buttons stop working, I don't think you're saving money. Cheapest isn't always the best way to go.