I bought a mallard machine this year.

Pros:

It does bring the ducks in for a look.
It will work in conjunction with other types of mojos to help your situation.

Cons:

I carry my set up in a large back back. It's not to heavy due to the small twelve volts on the market today.

It takes a total of ten minutes to set up, if the water is deep enough. You need water as deep as your knees or right over to dunk the decoys. Anything shallower your just stirring up the water.

I like it.

The best thing on the market that I have seen work this year are the mallard jack kites that you put on sixteen foot poles. They fly with barely a breeze and when they fly, they dip and dart like a real duck. Now we are talking about bringing down ducks