I bought both the D and G whistles together as postage was no more for one (£7ish to UK) than two. I've just taken up whistle, but got skilled friends to test my new ones. I bought on recommendation from someone at a workshop. We compared hers with various others. iIt compared well with a much more expensive Suzato and was far cheaper, and much better all round than a basic untuneable tin whistle, with a less harsh sound than one too.
Nice mellow tone, plays well and loudly enough through its range, not so temperature sensitive as a metal whistle, and plays nicely softly too (great for practicing without annoying the family/neighbours).
This whistle isn't actually one piece, as described on the website, but has a moveable/tunable head, which is rare in a whistle of this price range. It comes in a basic but adequate bag for the price with the D marked on the outside so you don't get the wrong one out in a hurry.
Quite delighted with my whistles!