I just thought I’d add my praises for this whistle. I got the blue-top nickel model. The sound is beautiful throughout the range. The 2nd octave has just a sexy amount of breathiness without sounding hoarse. Once I started playing this whistle I didn’t want to play any others. What a great deal for ten bucks!
The Gen Bb seem to be one of those incredibly inconsistent whistles. Some people will report getting really crappy ones. I bought a Bb blue top early in my whistle carreer and it was a very good one, very flutey sort of sound, very mellow troughout the range. Unfortunately I destroyed it in a tweaking craze where I tweaked all my Generations, most of them became better. The Eb for instance was terrific after tweaking, I even took the head from that one (a blue top) to use on a D brass tube and the sound was as good as any of Moloney’s or Bergin’s Generations I have heard (wish my own sound was that good). Sadly, that one was lost, fell out of my pocket at some point during some night. The Bb was totally destroyed by the tweaking and I haven’t since found any other Gen Bb like it (I’ve tried them occationally at music stores).
Because of the wider bore I ended up using the Bb after gigs as a straw to drink
whisky 
Incredibly inconsistant? Gen Bb’s? 
Seems like the D’s would better fall under this category. At least in my personal experience. And it seems like every other week there’s some new person on here going on about how much they love their Gen Bb… So you must of had some bad luck with yours. I bought two, one about 4 years ago, and another about 2 years ago. I made a B out of the later, but both played like champions even without my tweaking.
For the record, this appears to be a “one-dot” Gen Bb.
I bought it after listening to a number of people playing them in various recordings, and after reading so many positive things about them here–even after swearing off WhOA. But this is different anyway; it’s a different key. I can stop anytime I want.
I particularly like the hint of huskiness in the 2nd octave.