Essentially, you are talking a small difference, an inch between 210mm and 240mm, 8" versus 9" is not much. If I was buying a one-knife-for-all-duties knife, I would get the 240mm. Of course, this is an eternal debate, I have had great cooks argue both sides, that a shorter chef's knife is lighter and more responsive...a longer one is more versatile and offers longer stroke length to get more work done.
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
"perhaps...but then again...maybe not..."