I went to the oem store for my wifes charger and that's when I noticed they don't list the output. So I'd go from charging at a high rate to charging at an unknown but assumed safe rate. I checked the battery and it is 1500mAh, so charging at 2amps should be ok for the battery but I really have no clue how these phones regulate the charging and if they can take this kind of abuse. I agree with you and tend to like oem everything too. In this case oem leaves us hanging. This might not be a big deal but I just got my phone and I really don't want to kill it.
Fyi I'm using my wifes iphone as a guinea pig with an oem charger. She's almost ready for a 4g anyway so please don't think I'm too cruel