I tend to prefer blue Bbags, although I have bought other colors. There something about their blues, especially in the city style that feels just right to me (and worth the $$$).
For blacks and browns, I'm increasingly finding that I can feel very happy with mid-level brands that still have gorgeous leather (e.g., Hayden-Harnett, Gerard Darel).
I tend not to buy the same colors in different brands unless their different sizes and functions. I recently debated about buying a cobalt HH havana hobo, but decided not to because the color is quite similar to blueberry (which I have in the city). However, I eventually may find a way to rationalize that it's a different type of style.