That's a fair point. NSDateFormatter is fast enough and you should never replace it for anything else unless you know for sure that it's a problem. Well that goes for any optimization. In my particular case, it was really a bottleneck, and the time difference of 100 seconds vs 7 seconds meant a user will not have to wait for 93 seconds during the initial import step. I am not suggesting we start getting rid of NSDateFormatter as it is a very valuable tool which we use for any and all date formatting ourselves, just not during massive imports anymore.