This is a provisional rating, based on one-time use in worst-case conditions. The leaves were damp and in some cases wet, blown together and snowed on early the day before. The snow was gone, but there was little time or sun for drying things out.
First, I had scattered, damp to wet leaves on a patio, and blew them off with no issue, using the concentrator head and normal speed. I also removed them from a wood-chip path through a large garden, without picking up the wood chips. Again, damp to wet leaves. See above for results.
Second, I had leaves in a ditch that had been concentrated by wind and then rain/snowed on. The very top layer was moderately dry. Suction at normal speed did a good job picking them up. I was trying to take off a thin layer at a time, but occasionally a big clump would go through, with no problem. There was no clogging in the impeller area, and none in the flexible hose once I figured out when the bag was almost full. As you can see from the photo, I did not achieve 16:1 breakdown. In fact, there were some whole leaves still present, albeit crumpled. There still was a significant reduction, and I look forward to seeing how good it is with actual dry leaves. I filled a paper yard waste bag to the top with four full backpacks worth, and the bag weighed significantly more than a bag I had filled with damp/wet raked leaves which I had packed down as much as I could. Just the time saved from packing leaves makes the item worth the price. I love the backpack bag with it's large, folding closure. It was easy to open, close and empty, and remained remarkably dry after handling all those wet leaves. And if you connect the snaps without folding, it holds the bag open so it can get rid of any moisture. It appears quite sturdy, as does the item in general, and I expect to get a lot of use from it. I also tried the vac on more scattered leaves, and it did a good job of picking those up. In fact, it picked damp leaves off our gravel drive without disturbing the gravel.
All in all, it exceeded my expectations for the conditions I was working in. I look forward to seeing how it does under optimal conditions.