I have the Agri-Fab, bought at a local Lowe's. We have used it several times, and have had no problems. Yes, there are several parts and a bit of assembly required, however, an air powered ratchet is a BIG help.
I areate in the spring, and in the fall..when the ground is somewhat moist from the rains...learned that at a Golf Course..
We run 3 and sometimes 4 'cap block' on the weight tray..depending on if we are burying the coreing tubes or not. A normal block is approx. 40lb., but these have one end 'filled in', and are heavier.
We use a 43 year old, 7hp, belt drive to the drive shaft, Cub Cadet, in 2nd gear, at half throttle, with 8.5" AG tires, and no additional weight on the tractor, and that little CC pulls the rig up hill no problem. We tried the Turf tire and weights route, and couldn't get the tractor to pull uphill without spinning the tires like crazy. Going slower seems to do a better job, it lets the weight push the coring tubes completely down, and doesn't really allow the tubes to 'bounce' on the surface.
Here is what my areating set up looks like:
A week or two after areating, we then spread 'weed and feed' on the yard, using this high dollar/high tech set up ROF Note, this actual pic was taken a while after we had areated this year, and was during the time we were spreading the weed and feed.
In early to mid summer here in OH, our grass is still growing nicely, is the greenest of the neighbors on either side of me, and has no dead looking appearance...please see pic: