What whistle I use depends on the situation, but for almost all band gigs (esp. if I may not have a good monitor mix, or none at all), I always use the Susatos first. Intonation and volume are great. If I have a good monitor mix, then I’ll use my Copeland D (I only have the high and low D).
I played at a church last Sunday with a nice sound system and used a Susato low A…it had a very nice tone through the PA. My only complaint is the finger spacing, the last hole in particular…it’s a little too far down the end for my tastes.
And I almost always use a Generation for sitting around the house or a session.