Both API and Kordon NovAqua Plus conditioners handle chloramine, according to their respective websites. I've no idea if Prime somehow does this better, but I would suspect not.
My only reason not to use Prime is that it also somehow interferes with nitrite and nitrate, and when this is not required, it is best to leave nature alone. Seachem themselves, in response to my direct question, stated they do not fully understand how this happens:
The detoxification of nitrite and nitrate by Prime (when used at elevated levels) is not well understood from a mechanistic standpoint. The most likely explanation is that the nitrite and nitrate is removed in a manner similar to the way ammonia is removed; i.e. it is bound and held in a inert state until such time that bacteria in the biological filter are able to take a hold of it, break it apart and use it. Two other possible scenarios are reduction to nitrogen (N2) gas or conversion into a benign organic nitrogen compound.
I wish we had some more "concrete" explanation, but the end result is the same, it does actually detoxify nitrite and nitrate. This was unexpected chemically and thus initially we were not even aware of this, however we received numerous reports from customers stating that when they overdosed with Prime they were able to reduce or eliminate the high death rates they experienced when their nitrite and nitrate levels were high. We have received enough reports to date to ensure that this is no fluke and is in fact a verifiable function of the product.
The less chemical intrusion into the aquarium, the better, that's all I'm suggesting.