Neither - I would not hesitate using another Trigg coupling, no slapping during towing, far better direct connection, the poly block acts as a shock absorber. (thats TRIGG not TREG)
My current camper has a Oz Hitch, sure its a little less fiddly to hitch up, but for me the way a hitch works during travel is the most important factor. The poly's are a far better, tighter, direct connection. The Oz Hitch does slap during towing.
In terms of articulation, lets face it most ya'll will never utilise any off road hitch to their full spectrum, and poly blocks are more than adequate.