Best is hard to pin down when talking about just about anything. But for me...
Started with a Johnny Stewart PM3, with the 50' cord. It called critters but was a pain with the cord of course.
Got a Foxpro, a Wildfire. Small, but worked, remote wasn't great and left me wanting better.
Fury, better than the Wildfire and better remote, still not what I was looking for
Fusion, more features than the Fury but still left me wanting. Nice remote with the tx1000 but if it was behind me, or around a hill it didn't work. Needed an extra speaker out here in the open. And what's worse, went through some serious dry spells without calling anything.
LD Revolt, more than loud enough for any realistic situation, the vocals were a game changer for me, cost was very reasonable at that time. The remote works well, though it and the call are more cheaply put together than a foxpro for sure. The remote does some funny things sometimes when trying to shut down and I'm on my second remote which Rick sent at no charge several years ago now. Battery pack will run it for at least 2 days I'm sure. Let's put it this way, I'm not looking for another caller until this one craps out.
It sounds like the newer foxpros are really good also, and they've added a lot of sounds they didn't have a few years ago I guess.