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.
Whip It Off, Chambers!
"perhaps...but then again...maybe not..."