<<It's not who hits the hold first that gets out first it's who is the lowest.>>
Not always the case at busiest airports. ATC will usually try to set up the best landing stream in terms of VORTEX spacing...so, several heavies might be taken off the hold together, followed by a string of mediums, etc., irrespective of where they are vertically in the hold. You'll still get the same EAT as, has already been stated, this will be set up well in advance.