Millcreekis the best. I have a 60" model. Trust me they are heavy. The entire lower frame is made from 1.5" thick solid steel,the rest is 1/4" or 3/8" plate. They are heavy. But pricy. $1600 for a 60" 3pt. Then another $400 to $800 for weights. Mine weights 1100 pounds or so.
The woods/gill pl 60 is heavier than the classen or the millcreek. Substantially heavier. I checked out all the 3 Pt aerators, the woods was a tank,96 tines,independent tine gang wheels, 450 lbs curb weight and a weight tray designed to hold 1000 lbs. The millcreek and classen machines are fine and will do a good job for you, if you want the war wagon of all 3 pt. aerators check out the woods!
As a note for weighting those with an upper rack, like the classens, we liked to take a set of cinderblocks, a large Ubolt with nuts and flat washers on it and fill the openings with quickset cement, having the Ubolts protude as handles. Why? on super saturated turfs, or steep hillsides. you can unload blocks in different positions to keep from sinking to the axles on it. Load em all and they will punch even the hardest clay soils. Use a tie down strap to keep the blocks in place while riding, threaded through the handles. The quick on and off becomes extremely useful when it comes time to trailer it or move it by hand. The one other mod we made to our 60" classens was to cut the axle out, separate each tine set from the old axle the put it back in over a new solid axle using tube spacers and washers to keep them apart. Why? We pulled them with riding z-turners and this allowed them to turn in a very tight (z)radius without tearing the turf. A matter of insides turning slower than outsides. Easy and inexpensive to do for anyone experienced working with metal at all. It also allows you to do denser tine packing by simply changing the size of spacers and sliding more tine spindles in.
The woods/gill aerators come out of the factory with independent gang wheels that allow turning without any lock up, each tine gang wheel has it's own bearings and grease fitting. Four inch cores, serious aeration, hit a sprinkler head & its history!