I just got my WhiteCap Generation D whistle from Mack Hoover and I must tell tell the world, it is one sweet playing whistle. 
It does play differently than the standard Generation, but after a few passes through the “Star of County Down” I got it handled.
Yep. Love mine too. It’s a great paractice whistle cause it’s quiet and pleasant to play.
I am patiently waiting for my White Cap Oak. I think I will be as pleased as you guys.
Ron
My patience is rewarded. The Hoover/Oak arrived today. It is all that I had hoped for. A very bright sounding whistle with a little different breath control required. I like it much better than the original Oak. I now have three whistles that give me the kind of diversity in sound that I like depending on how I feel on a particular day. This has become one of my three most favorite whistles.
If you look in on this thread Mack it is great. I will get the Oak tube in the mail tomorrow.
Happy Hoovering
Ron