It seems that the convergence of FASB/IASB is inevitable now, so what are the benefits of being an early adopter to IFRS?

The sooner the companies conduct an impact analysis for the adoption of IFRS, the better it will be for the future of their companies. This will allow the companies to actually assess the impact of the IFRS as and when it is adopted to better structure the complex transactions.

Other than that, at present, I do not see any real impact of the companies early adopting the IFRS. I have included some background information below, for the growing importance of the incorporation of IFRS in the U.S.

BACKGROUND:
The world is a more flatter / global work place than what it was a decade back. Hence, there is a more a growing need for global accounting standards, be it IFRS or any other accounting standards. Personally, I would have preferred something like new accounting standards such as "Globally Improved Reporting Standards" that would have incorporated the best of all the accounting standards from all over the world. However, it seems that IFRS has been gaining more prominence all over the world.

In the U.S., due to increased use of IFRS all over the world and also partly from the pressure from G-20, in 2007 the SEC announced that the financials statements could be reported under IFRS, without any reconciliation to the U.S. GAAP. This is reason you will see more and more companies filing with the SEC only under IFRS, with no reconciliations to the U.S. GAAP. Hence, the prominence of IFRS will continue to increase in the U.S. as more and more countries continue to start reporting under IFRS (e.g. Chile, Brazil, Canada, etc.)