Another difference is that the ATF in the Bush administration tried to track the the guns. They canceled it when they couldn't.
Yeah, the Bush administration stuff has been known for some time now but we should expect to keep hearing about it. As more of the mainstream press show interest, the more political this will be made to look. As others here have posted, wrong is wrong and if some of that falls on the previous administration, so be it.
In addition, this is becoming a bigger scandal because of the dodgy moves from the DOJ and Holder.