You may remember that Brian (MtnViewRanch) stayed with us while he was attending the Ag Fair.
He brought his giant Road Grader for me to try out. I finally dried up enough so I could. It's bigger than my 7' boxblade and possibly even heavier? Longer and wider for sure. Anyway, once I got it hooked (he had no pins on it) I dragged it around the road many times. The blades cut very good and in fact, more than I really wanted. I had to fiddle around with the Top and Tilt and position control to get it so both blades were cutting just a little bit. Once I got the setting correct, it was easy to drag and level the road.
My 55hp Kama handled the big blade easily.
I noticed that the added length of this blade could get the road a little more level that my boxblade ... at least in theory. Not necessarily smoother, but more level from point to point. It acts like a land plane. The blades on it are very aggressive and have more cutting angle than my box blade. It did get it to cut off few humps and bumps and popped out some rocks that the box blade jumped over before. I went over the road several times with it. There are less little bumps in it than before, so it did a really good job of leveling.
One thing I noticed was that the (now) loose soil would spill over the blades and back onto the road. The other thing I noticed that loose rocks became easily stuck under the blade. Parts of the road that were already smooth and hard where it didn't cut as much came out fine. But other parts I had to go back over to smooth the loose soil down and get rid of the rocks. I removed the Grader blade and put on my box blade (photos below). It collected the loose rocks and soil and really smoothed the road out.
Over all, my Opinion is that the Grader is a specialty implement designed more for leveling a rough surface into a smooth level roadway. The boxblade is more versatile being as you can use it to cut gutters, move dirt backwards and smooth by tilting all the way back to use the rear smoothing blade only. I believe the box blade would be handier to establish a road or trail first to cut it and pitch it and cut the gutters. Then use the grader to level it more and finally, the box blade again to smooth it all out.
Having both of these implements would be good for road prep and finishing. But if I could only have one, I'd still choose the box blade for me.
Rob-