David B has both libraries and seems to prefer Modern U because it's clear and direct (no room ambience). Another poster likes the Bosendorfer Upright more because of its mellow tone. Here's a post where both libraries are mentioned:
I read all the posts you linked me and it was very helpful. Thank you
I just purchased Modern U and I have the Bosendorfer Upright also. You probably won't go far wrong with either of these two.
Thank you for your detailed explanation! I have VSL CFX and D-274 and planned to upgrade to full version of Bundle, but I changed my mind to purchase only the Bosendorfer Standard separately to purchase Modern U later. When I listen to the official demo or watch YouTube videos, Modern U seemed to be an instrument that impresses the piano player a little more as you said. However, considering that VSL Bosendorfer is a little ahead of the dynamic range and that Bosendorfer 130 is a better piano than Yamaha U3, having a VSL with Modern U would not be a bad choice! My wallet is the only problem.
Here is a comparison between VI Labs Modern U and the VSL Bösendorfer 130 upright pianos. I currently prefer the Modern U. It seems to have a more direct, clear, and powerful sound in the samples. The Bösendorfer is warm, mellow, and has a softer sound to it.
Here you go.
Including this video, thanks to the demos you played on your YouTube channel. They helped me a lot in my choice. I'll buy the standard of VSL Bosendorfer first, and buy Modern U when there is a discount event of it later. Thank you, David.