I wouldn't call them trash, but they definitely leave more to be desired. Think of it this way, you're paying $X for the head, and the legs are only an afterthought. Obviously they aren't going to be very good.
I use the 2-stage Solo DV CF legs with my Cine DSLR head, and I can't possibly imagine using aluminum legs. The CF legs alone are insanely light (I thought the box was empty when it arrived at my doorstep), but once you feel how heavy Sachtler heads are you're going to shudder at the thought of adding more weight. I actually redesigned my entire kit (skis, outerwear, boots, touring bindings, camera, legs, etc.) to compensate for my tripod head.