I also have the XLR cables (990/7500); they're stiff, but not really an issue for my setup. I would assume that the plastic jacket that the cable is enclosed in gives them their stiffness. They are well built (they look like they came out of a B-1 bomber).
As you stated, the 7500 is heavy-almost needed a chainfall and a come-along to get it into the rack.
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Anthem MRX-500/ Outlaw 7500, Paradigm Studio 100's Fronts, Paradigm CC-590 Center, Phase Technology Dipole rears , Martin Logan Dynamo sub, Oppo BDP-103, DIRECTV H22-200 DVR HD receiver, Samsung PN60E8000 3D Plasma 60"
2nd System
B&K ST 202 Amp, Outlaw 990, Rotel RCD 1072CD, Yaqin CD 1 Tube Buffer, Apogee Centaur Minors, Phase Technology Model 10 Sub, Rotel RP-855 turntable, Panasonic DMP-BD30, DIRECTV H21-700 DVR HD receiver, Free Agent Home Theatre+, Vizio 40" LED