I don't think you can get a diamond with the same grading as a Tiffany's diamond for 1/3 of the cost. A diamond isn't just a diamond, there's a grading system for quality. If you get a diamond with the same grading as Tiff's from a no-name brand, you would save money, but not at 1/3 of the cost. Plus you get free cleaning, polishing, and great service for the rest of your life for free with Tiffany's.
I never said that MontBlanc is just a fashion brand. I'm not saying that they're like Burberry or Gucci's watch department. If anything, MontBlanc is like Louis Vuitton's watch depart. Very well made watches, but still, it's Louis Vuitton. Regardless of a caliber movement... it's Louis Vuitton.
Would you rather buy a Grand Seiko over a Rolex Milgauss? I know their movement embarrasses a Rolex movement (because it's Seiko and it's better), but I'd still choose the Rolex.
I guess... to each his own. Right?