In the absence of any other considerations I'd say pretty much the same as Dave has. I think the triangulated setup has an advantage in traversing uneven pavement (visualize one end of the axle going up while the other maintains or drops), less "bind" on the upper arms (parallel 4 bar guys will likely deny they've ever experienced this, but I would suggest that's because they have no immediate comparative to judge against).

That being said, exhaust routing with triangulated arms becomes more of a challenge, and the bulk and heat vulnerability of air bags adds to that. If you've got enough "real estate" I'd vote for triangulated, otherwise the parallel system, complete with panhard bar may make for easier/better packaging of all your component needs.