Kinda depends upon what you're you're going to pull them with. But generally neither will do the whole job satisfactorily, as what you want to do is often a two stage process. Together, they make the job a breeze. The chain harrow (I assume that's what you mean by drag harrow rake ) is excellent for smoothing/leveling loose gravel, but it can't break it up in the first place. That's where the box blade comes in. The box blade does the grunt work; scraping the center hump and breaking up the potholes, then level/smooth/dress with the chain harrow.
If you bought the chain harrow only, dress the gravel weekly with before traffic has a chance to compact everything. Even though my 8x9 chain harrow weighs nearly 500 pounds, there's still not enough weight there to break up a compacted gravel roadbed. If you bought the box blade only, you'll be disappointed at not ever quite getting that "finished look". But together, they're a great pair.
Or does drag harrow rake perhaps mean a landscape rake?
//greg//