Talos,
I was once like you, I had an "Irvin" style sheepskin bomber and a lambskin "A-2'sh" jacket and I was as happy as can be. Then I found these forums and those jackets are long gone. They have been replaced with Aero's and Good Wear's. I'm still as happy as can be, but my bank account is many thousands of dollars lighter! If a black B3 is what you want, go for it and be happy, then leave this place and never look back, your bank account will thank you for it. If however, you think you might be interested in the origins of these designs and the history behind them, stick around and read on, there is a wealth of info hear, and even more over at the VLJ, but be forewarned it can become an addiction.
As for the question about the B3 vs D1. The fleece on a D1 is about half as thick as that of a B3, by original specs(, some modern manufactures will vary), so the B3 is much warmer. I live in Canada and my D1 sees a lot more use than my B3. By the time it's actually cold enough to wear a B3 around here I prefer a parka.
B
Is it okay to both own a black B3 AND stay on the Lounge? I hope so because, as you note, "there is a wealth of info hear(sic)," and I'd really like to stay!