They are both decent sites, both with a downside.
Love polymatchmaker cuz obviously, everyone's poly, and I've found really good possible matches. Downside---none (yet) are in my state.
OKcupid is better for getting local matches. Downside---you have to sift thru tons of monos to find some good polys. I got real tired of explaining myself to people who answered my ad, so I put "polyamory" and "polyamorous" and "Non-monogamy" ALL OVER my ad text. Sad I had to be practically shining a "poly" neon sign to keep the husband-hunters away.