I have worked with both the Letus and the RedRock adapters once only and I will not again.
The RedRock (a "rental") was used on a music video specifically because it created a finite focus point in the center of the frame. Selective focus was the look that the director wanted and we didn't have to make any adjustments to create that centralized focus because of the inherent qualities in the RedRock.
When I was given a choice between the Letus and the RedRock for a short film, I chose the Letus, knowing the focus issue with the RedRock. However, I was very disappointed in the Letus. It performed ok with wide angle lenses, but I would avoid any long lens use. It was impossible to have anything in focus on the 200mm.
All that being said, I recommend only using the P+S Technik adapter. It is the hands down the best adapter out there. It does exactly what you want it to do without any problems.
All of the lens adapters mentioned were used on the HVX200 and various prime lenses.