O1 experience is very helpful for EB1a application

The standards set for O1 and EB1a are not exactly the same. This is not difficult to understand: O1 belongs to non-immigrant visa while EB1a is a way for getting immigrant visa. So it is not surprising to find some of the O1 holders finally get their EB1a applications approved but others do not.

However, O1 experience is definitely a remarkable credit for EB1a application. Most of the O1 supporting documents can be very useful for EB1a application after a proper reorganization.

Good luck!