It also depends on the situation, intially I was admitted in partial waiver but after one year, I became lucky and I got a RA, not best but it is sufficient at that time, pretty cool. Now the situation has changed, I tried 4 months to get RA with GRE, no luck. But accidently, because of my good experiance, best schools are also interested in my resume and mentioned me to give GRE and just appear, but I didn't give GRE, finally, I got a really good offer from my own school but I have some other admission at this time.