I have had no issues with frame rates, the online reviews i have seen say ORBX gets you better frame rates but i'm sure you could find some that go the other way to. I got down to the choice between ORBX and GE and picked ORBX. Doesn't make it right or wrong, just what I did.
I have seen no negative FR issues with ORBX, using global and vector. I do not have the third level (Pacific NW, England, etc etc)