The first whistle I ever played was a Generation D.
It was all there was then, and you just made them work (which, by and large, they did).
I would still play one if the occasion demanded but nowadays tend to play other makes.
In truth it doesn't matter who made your whistle, so long as it does what you want it to.
My normal whistles of choice nowadays (for C, D, E flat, F) are Chris Abells because they
record so beautifully but, at times, I've used a Kerry D or a Susato D or E flat or a Harper
D or C, depending on the sound required or, to put it more simply, whatever sounds best
in the track(!) That's the bottom line.
Recently, on a film score, I had to play a line in unison with the violin section and it
could only be done on an F Sharp. I had a Kerry in my case, so tried that. It sounded
good, but then Eric Rigler, who was also on the gig, said "I thought I had to play that
line so I had Michael Burke send me this composite F Sharp. Want to try it?"
I did, and it blended better with the violins. Nothing wrong with either whistle - you
simply use whatever works best for that particular moment. Horses for courses.
(When the sessions were over I traded Eric a spare Low A for his composite!)
There is a bewildering array of "Low" whistles on the market ever since Bernard
Overton invented them, and each player will find the instrument he likes (as in, one Sax
player uses Selmer whilst the next guy prefers Yamaha etc. etc.).
I tend to stick to Kerry and Chieftain, simply because Phil Hardy made them for me in every key known to mankind, (and a few yet to be discovered), to play on the "Titanic" score, and I've grown accustomed to them. Also, in terms of metal whistles,
I've never come across anything better. If you stumble upon one of his brass ones for sale, (he doesn't make them anymore) grab it!!
Some people use plastic whistles but I've rarely found a use for them.
Wooden whistles - now that's another story. Phil Hardy has a couple of low whistles
by Jonathan Swayne. Wish I did.