Despite the proliferation and popularity of drop-away designs I am going to be putting a Golden Key Futura Infinity rest on my single cam Patriot. I like the microadjustability and ruggedness of the design.

I have tried all of the drop aways you mentioned and found each of them to have their advantages and disadvantages. The Muzzy has been around the longest and seems to have proven itself under most situations. The Power drop is probably the newest design but shows promise. The Drop zone is of the typical cable-linkage design but I like its rugged style and ease of adjustability.

Hope this helps some.