Chadley, shaker grates are a huge huge deal to me and most of my customers. Makes cleanup super easy, work a handle and all your ash falls into the pan.
However with the earth design, the grate system is kinda a poor design and don't benefit much. I've seen 2 people with earth customers lay plate steel over the existing grates because they were a hassle and let to many big chunks through, that part of the earth furnace, IMO is a poor design.
If I were going to buy an earth it would def be the non grate model, they made more btu's and the firebox door is 5" bigger! Always nice to have!
When burning a furnace with no grates, you can burn and burn until your ashes stir around and they'll get so fine they look like liquid. When you burn them this fine it's no big deal to take a few scoops out now and then