AGM batteries have been around for a long time. I'm just seeing them used in cars though. The electrolyte is absorbed so the battery can be installed on it's side. That's why they have been used in motorcycles and ATVs for a while.
They take a little higher charge wattage. Any modern smart charger will have an AGM setting. They also have a much slower self discharge rate. So if you drive your car more than just a few miles a week you will probably never need a trickle charger.
Not sure if the life expectancy is as high as led acid though. I've never owned anything with an AGM long enough to know.