I've been using the 20lb recently for mixed ground and it seems very good & strong. In fact a while back I was fishing Shields pier with a mate who was also using the stuff in 18lb, and we both kept fastening up on what felt like a rope. In the dark both of us had real fun & games trying to snap the stuff, getting sliced hands trying to keep the line clear of the wall while the other pulled for a break, and believe me it took some snapping. In fact on my last chuck I managed to pull out of the snag, retrieving a bundle of old line & sinkers & stuff, so I rate it pretty highly. I can only imagine the 30lb stuff would be fine for rough ground and the 45lb stuff is the same diameter as the 30lb line I normally use.
Gary