Hello, the Amazing Chiffboard!
As a ‘relative newbie’, I’ve actually playing the tinwhistle for about a year and a half (albeit being still a short period of time). And now I find that I want a better high whistle. I own a self-tweaked Feadog C, a Clarke Original D, a Dixon alto G, a pretty good self-tweaked Generation B flat and a Reviol Low D. But personally I don’t enjoy the sound of the Dixon much. And I find the rest of them being really good. 
And now I want a better-sounding soprano whistle. I really enjoy the sound of the O’Riordan for its sweetness and pureness, and I also like the Clarke Original very much, for its mellow tone. After huge amounts of researching, I have several whistles in my mind: Oz, Burke, Bracker and Shaw.
So I’d like to know the differences between those whistles. I know the Oz and the Burke are unarguably great, both being very clear and pure, but what’s the difference between the Oz and the Burke? 
And I find that the Bracker is also good, so I want to learn about the differences between the Burke and the Bracker. For the Shaw, I think it may sound like my favourite Clarke Original, so I also would like to compare the Shaw to the Clarke. What’s your opinion? 
I’d also like to hear other suggestions as well.~ 
Regards,
Max
(Forgive my English if it’s not good.)
Don’t know about the Bracker and Oz.
I own Burkes in several keys. They’re great for orchestral work but perhaps take too much air and aren’t as nimble in the 2nd octave as some would prefer, for ITM.
I’ve tried some Shaws, which took an unacceptable amount of air and had unimpressive tone. However Shaws, like Clarkes, have the enormous advantage that you can easily change the voicing by lowering the windway and changing the position and shape of the blade. And, you can easily un-do anything you do. You can end up with a very nice whistle if you’re willing to put in the time. I’ve done that with an old Clarke C and came out with an exceptionally good whistle. I’ve not done it with a Shaw but it should work just as well.
Since they play great and are relatively inexpensive I might recommend that you try a Killarney. Mine has a supremely sweet easy 2nd octave yet a full nice low range. However I will say that I’ve played vintage Generations which were better, better in fact than any other D I’ve tried.
I’ve been playing for about 3 years and started on a Dixon aluminium high D which was great to start with.
After much internet research and listening to various clips, I have bought a Ronaldo Rayburn brass narrow bore high D in ‘just’ tuning. It’s a lovely sounding whistle, very melodious and I love it!
Now looking to buy a Burke session whistle for a bit more punch.
My advice is to listen to clips of as many as you can and buy the one you like 
I really like the Dixon brand. I prefer the polymer as the brass Trad was too harsh for me. But the polymer has just the right balance of tone.
Have you considered the Syn? I got a set from Whistle and Drum and am very happy with them. Easy to play and lovely sound.
Also consider Gene Milligan’s. I went through 4 or 5 high d’s before I got one of his. Now I play it almost exclusively.