Which would best for thick grass and weeds? 

between the two, power pro can cut through the weed better. but if you want something really good for grass, go with maxquatro X4 braid

I find the V2 to be smoother then Suffix.  Check out Berkley X5, its textured and thinner then other braids in similar lb test which makes it cut through grass really well, while still having good knot strength.

For cutting through weeds original PP would be best.