It beats the 266, not sure about the 333.
I'm guessing your familiar with Ace's hardware, and know he does respectable/accurate reviews (as opposed to Toms hardware)... heres a sockket A shootout he did:
http://aceshardware.com/read.jsp?id=45000290
(he didn't test any of the 333, i think the article was made right around the same time the 333 was being released)
Clearance, well, its pretty good, not really the best, but you should look for youself (newegg has some desent pictures). it does have the 4 drilled holes... pretty standard with most newer AMD boards.
As for Ram, well.. how much you going to overclock, I'm not sure if any brands have problkems with the board (don't think so)... Corsair, crucial, etc. are of course the top choices to use. I prefer Corsair PC2700 personally.