As a Harrisburg-area native, it's barely closer than the King of Prussia store (15 mins tops). If I'm going to drive 1-1.5 hrs to get to an Apple store, I'd probably pick King of Prussia given that it's a mega mall mecca. In reality though, the odds of my having interest in driving that far to shop are really really low, super mega ultra low, lowest limbo possible kind-of-low. Even for Apple. Now, if the Harrisburg/Lancaster/York area could support a store, my bank accounts would be severely threatened...
I went to college in the Lehigh Valley (Lafayette); they're just 15+ yrs too late... Any Apple store in PA is a good Apple store though - we just need more.