FoxPro is the way to go. I use mine all year, it does a great job on coyotes, lots of options for sounds. I like to make my own on hand calls and load them on to the unit.
In the fall I have used deer calls with great success. One sequence I have is a buck fight, stomping, rattling, granting, sparring.. Right sound at the right time makes for some entertainment! But as mentioned, no turkeys or waterfowl.
The units are not small, so some hand calls are handy too. I hunt coyotes almost daily, the FoxPro can draw in the weary dogs at times hand calls can't. Give a major advantage in situations where the wind or cover isn't ideal.
Hunted coyotes for a living for almost 20 years, best investment I have ever made.