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@gbj_tester
Well, that's in the ballpark for weight with generic net-shape forgings, so it comes down to stiffness. It's actually quite hard to make an aluminium stem stiffer without making it heavier, unless you venture outside the bounds set by the 31.8 x 35-40 bar clamp and 28.6 x 40-44 steerer clamp. You basically need to get the metal of the beam section as far from the axis as possible, and hardly anybody ventures outside the aforesaid envelope. My critique of the BMW stem was strictly constrained to the poor steerer clamp design. The Crank Bros stem has a different, but equally problematic issue with the clamps; wedge clamps are prone to generating asymmetric compression loads on the cylinder they are clamping, which might be a problem with thin walled bars and steerers, especially carbon ones. The ideal clamp has as little bending stiffness as possible, so that the tension and therefore clamping pressure remains uniform around the whole circumference. You want it to be like a girth strap, not a saddle. If you must include some bending stiffness in a clamp, it needs to be precisely machined to match the profile of the clamped item when stressed; this is guaranteed to be impossible with a wedge clamp, since the clamped item has too large a tolerance on both OD and roundness.
I leave anaesthetic judgements to the individual user; I sometimes give a personal opinion but it has no more weight than anybody else's subjective view.