I don't play the Howard very often,as the finger holes are large and notes above 2nd octave G are harder to hit cleanly than my other low D whistles.
Though having said that,it's probably down to lack of practice on my part-I got the Howard out again when I saw your question,and guess what?-It IS a GOOD WHISTLE!
I had been thinking about selling it,but I think that it's a keeper now.
The tone is definately different from any other Low whistle,It's very much a rich,low WHISTLE sound (especially in the lower octave),whereas the Copeland is 'Flutey'.
I think the lesson to be learnt is that when you are a whistle COLLECTOR,you tend to neglect some of your instruments,and really don't get to play them to their full potential.
Sometimes,you really don't appreciate just what you already have!
So,in essence, my 're-discovery means that it's almost like receiving a 'new' instrument,my second in the last week,as I also cleaned up a battered old wooden descant Recorder,and found it was playable.