Generally DC charger could have a higher charge rate that most AC/DC charger. Most AC/DC charger will only have a 6amp charge rate. The reasoning behind that, IMO, is to keep the cost and weight down for the charger. When you charge at a higher current, you would need a bigger power supply to do so. This would only make the charger more expensive, bigger and heavier. That being said, there are some high current/capacity chargers that are AC/DC. SkyRC D100 and D200 being one of them

You have more choices with DC chargers. There are numerous companies that makes all kinds of chargers to your needs. Power supplies can be found easily and they arent all that expensive. An old computer power supply, old server rack power supply, or cheapo 12V 20amp power supply from ebay would be enough. Also when you are in the field, you can hook up your charger to your car battery and charge a few cells for some extra run time (just be sure not to drain your car battery completely dead)

As to what charger to choose, if you are into club racing and competitive, or just want the most out of your batteries, you would want to get a good charger. You want a charger that have high precision and accuracy at measuring voltage and amperage so you wont over charge or discharge your batteries. Also you would want a charger that can measure the internal resistance of the battery so you can gauge the condition of the back and decide which one to use on your races.

Im a fan of iChargers since are pack full of all the features I just talked about. This is a nice charger if your only running 2S packs
http://www.hobbyking.com/hobbyking/s...e_Charger.html

The hobbyking charger you posted isnt bad. From what Ive read, its a iCharger 206B clone, but I question the build quality features. it might or might not have the internal resistance measurements