I have never heard of OBE.
Of course, I have never gone hunting for 4E 3PP products. Never felt the need.
Guess my experiences with sloppy inexperienced dreck during the 3E era made me realize only the very best in 3PP publishers are worth my time and effort: Malhavoc, Necromancer, Green Ronin, Penumbra...
And with the GSL as is, that critical mass simply isn't going to materialize for the fourth edition.
I fear lots of customers dont bother going above and beyond WotC; not only because 3PPs simply don't have the market presence they used to have; but because there is much truth to the suspicion those few 3PPs that's left simply can't compete with Wizards quality-wise.