What are the merits of filing a patent before the end of the grace period?

In the U.S., you are “patent pending” once you file an application, provisional or otherwise, and any filed application is an asset that may be transacted. The sooner an application is filed, the earlier the priority date (generally) and the smaller the universe of prior art which might be asserted against your non-provisional application would be. The one year “grace period” to which you are referring is a window in which the USPTO will allow you to disclose your invention, subject to certain conditions, without such disclosure itself become a prior art reference that would be found to preempt your invention once its non-provisional application is examined. The “grace period” does not directly have anything to do with others and their inventions / applications. The “grace period” is NOT some window in which you can refrain from filing an application and still hope to preempt others who might file applications for similar technology - since the American Invents Act was effective, the U.S. patent system is a “first to file” system and filing an application is what creates priority. From the nature of your question, you would likely receive significant benefit from speaking with patent counsel in private to craft a IP strategy.