I never realized that either of these existed. Since I have so much difficulty adjusting my riding tractor plastic mulch layer there is no way I would consider something like those. If I had a smaller operation I would just lay boards on the plastic edges, basically what I do inside my high tunnels.

They are new this year to Johnnys.

I built my own mulch layer, but an AH, HA moment yesterday. I have this really small space beside a tunnel and I decided to put it back into production, but it is really hard to use the mulch layer in a space that is only 15 feet wide. So after tilling, I just drove my tractor over the freshly tilled beds and I have a perfect shaped bed and then I can easily put the plastic mulch down by hand. Took about 5 minutes to do. Works great for 3 foot plastic. I like this flat bed for 4 rows of lettuce transplants.

After mulch

The mulch layer that is pulled behind a tractor also has a dirt scoop that makes a raised bed. There's a big difference between mulch laid flat and having a raised bed. It still works when it's flat, but water tends to pool on it, and vines rot if they lay in the water. Plus, you don't get the drainage and early season heating benefit of the raised bed.

I've been looking at both of these options and am wondering what you ended up doing and how your choice worked out.

Since you revived this thread I'll just point out that a 14 HP tractor with a 3 point hitch can handle a plastic layer if you don't shape the bed. My Kubota B6100 will allow plastic rows to be laid within 6" of each other if that is what is wanted.

Unlike Robbie, I see no advantage of a raised bed for the mile + of black plastic I lay every year. Raised beds dry out faster and require drip tape which I don't use anymore for field laid plastic. If you have well drained soil raised beds are a waste of power and time.