I recently bought the Jubilee Low D Whistle (plastic). I already had a Bamboo Low D to see if I liked playing the Low D. And I bought the Jubilee PVC Low D (and later a Calmont Low D–practice model) to make sure and to move up a bit. The Jubilee whistle has suprisingly solid volume and good tone.
Here is the link to the page: http://jubileeinstruments.messianic-webhosting.com/pr-lowdrev.htm
I think this really is a good model for those in the early stages of low D whistle playing. You have to adjust to using more air than a high D, of course, but the finger holes are reasonably sized and spaced well enough to allow for easier playing. Having this whistle will let you see if you want a more expensive whistle, but you’ll also have acquired a low whistle that plays beautifully.
I’d actually be curious to see if there are some on this forum who have the Bingamon plastic model and other more expensive low whistles and what they have found in comparison