Here are some tunes on the M&E polymer whistle:
This whistle must be blown hard. There's no other way to say it, and if the idea of a whistle that you can actually get physically worn out by playing doesn't appeal to you, you probably shouldn't get one of these.
That said, it doesn't take vast amounts of air, but it has some resistance that the air really has to be pushed. It does take more air than many other kinds of whistles, though.
Susatos get negative comments because they are "too loud." Cronnolly whistles are as loud as a clarinet with a pretty stiff reed. They are really too loud to play inside.
That said, the intonation and balance between octaves are quite good, the tone is pure with some chiff popping in between notes, and the whistle plays easily once you get used to it.
I think these are maybe the loudest whistle made.