In MOST cases, a box blade needs to be of sufficient weight REGARDLESS of scarifiers, draft control, or any other accessories, options, gimmicks, or wives tales. In theory the teeth should pull the box into the ground, but in practical application, that just doesn't happen most of the time.(unless you're dealing with "ideal circumstances") That doesn't mean weight is the ultimate solution, but you need those pounds. Look at what commercial landscapers, general contractors, and excavating contractors use. HEAVY boxes often in conjunction with tractors featuring hydraulic down pressure on the hitch. In many situations, you need the weight just to get the scarifiers to penetrate hard ground. Granted, on a small sub-compact or even some compacts, you wouldn't be able to make good use of that digging ability due to not enough traction or HP, but it's easier to gauge the heavier box UP with the hitch, preventing it from digging in too deep, than to repeatedly go over and over the same piece of ground just barely scratching the surface.
More expensive boxes are GENERALLY heavier, but there is no direct correlation between weight and cost. If a lower cost box is of ample strenght, weight can be added as needed, usually for considerabley less than the cost of a "premium" box.
I have a Wood HB84that's more than enough box for use on my 60 HP Deere and works like a charm on my 40 and 47 hp smaller tractors.