I don't think there is a dime's difference in bat performance between today's LS & Easton bats. Some difference in "feel", sure.
No, the BESR test is not an exact duplication of HS/college ball. But it is probably adequate to ensure that any differences are negligible.
They are all using essentially the same group of alloys. They all have the same engineering tools with which to design & analyze.
I bought Easton bats for Texan Son not because I thought they were a superior bat, but because Easton's warranty service was superior.
The real difference is the hitter holding the bat.