Aesthetics
It's a nice looking whistle. It is well made and well finished. The tuning slide works well - not too tight or too loose. The holes are smooth and well finished. If you look inside you can see some marks on the aluminium but this is a hand made whistle - on the outside it is lovely.
Design
I don't own many low whistles to compare it to. I have a Dixon polymer tapered bore Low D and I have also played a Chieftain v3 low D. Visually the Holifield is like the Chieftain. The fipple design is similar. The mouthpiece is comfortable. The holes are noticeably larger and further spaced apart than my Dixon (and also, from what I remember, the Chieftain). I have small hands and this took some getting used to. I can play it, but more care is needed. By comparison the Dixon feels much easier! The bore is wider than the Dixon whistle. In fact the end of the Dixon just fits into the end of the Holifield. It is slightly shorter than the Dixon (about half an inch).
Sound
As others have commented there is a lot of chiff to the sound! The Dixon has a 'purer' tone, and the Holifield is a little breathy by comparison. I know others who have reviewed the whistle weren't so keen on the sound. Personally I like it.
These things are subjective though. The volume is a little louder than my Dixon, but not as loud as I was expecting. The low register isn't much louder at all (I think the chiff clouds some of the tone) but the upper octave is louder and more 'positive' than the Dixon - you can feel that there is more power. I love the fact I can lean into the notes (in both octaves) and get more volume/energy without the sound breaking or jumping up to quickly. Moving between octaves is easy to control. It allows for nice dynamics, especially for slow airs (which suite this whistle I think). Breath requirements are greater than the Dixon but only slightly. Like most aluminium whistles it needs to warm up to sound its best. Conclusion
Personally I really liked the whistle. I can't compare it to many other models especially high-end models, but for the price I think it is outstanding. Would I buy one - perhaps! The one thing that makes me wary, for me, is the hole sizing and space compared with the size of my hands. I can play it, but it is a stretch and the diameter of my fingers compared with the holes does not give much room for error when fingering quickly. Do you plan to make a low Eb, or F?
Many thanks for letting me try it. I will send in on to the next person shortly.
Wayne