Though you may make the right call to invest early in a burgeoning market, unless you execute towards a leadership position, it's going to be a problematic investment. Choosing the right market is a necessary, though not sufficient ingredient for success. It's essential that the management team, supported by investors with sufficient capital and drive have a common objective.
To paint with a broad brush (exceptions abound) I think it's fair to say that there is a distinct difference between East coast and West coast investors and management teams. I believe that West coast investors and teams have been far more market share driven than their right coast sibling and believe that the preponderance of technology market share leaders being in the Valley is a direct result of this culture.
The Boston to NY corridor does have its share of companies which are showing great signs of success. Some look really great and have the potential to be market leaders, such as Tumblr, Payoneer, Etsy or 10Gen. But it's also fair to say that since the heyday of Doubleclick and AOL, we may not have a critical mass of companies which are hell bent on being market leaders, in markets which matter.