The Suwe Cortina is a very sophisticated device for 1954. It is largely aluminium and very light for the time (considerable lighter than the bronze 1953 Campagnolo Gran Sport). It is an under the chainstay parallelogram design, but it has two adjustment screws (as opposed to the 1955 GB Altenburger’s single one) and a pulley cage that pivots between the pulleys. The overall feel is of precision and quality, I even think that the parallelogram pivot pins might be stainless steel.
Weaknesses might include; the clamp mounting onto a round, tapering, tube - never a recipe for confidence - although the Suwe mount does include two pointed grub screws to gain some serious purchase, and the cable clamping arrangement, which looks a trifle flimsy.
It certainly looks like it would have given the Campagnolo Gran Sport some serious competition. I wonder why we do not hear more about it.