I have a 10 row, 100' long garden and needed a better way to plant seeds.  What I found is that the seeds are not dropped uniformly and tend to pop out of the bin like a pop corn machine.  I put plastic over the bin to hold them in but then you can't see if the seeds are being picked up by the plate.  I have tried it for two years and I'll have three seeds drop in one place and then none for eight feet or so.  The plate becomes loose and seeds get lodged behind the plate.  Your soil has to be perfectly tilled with no lumps, debris or rocks.  In a perfect world it might work, but I don't live in a perfect world.