The picture gives a good idea of proportion, though the more recent numbers we're getting for some individuals put T.rex right alongside even the high-end estimates for Giganotosaurus' length.
It's far from just ubiquity that, for me, makes T.rex sit head and shoulders above other large theropods. The brain case is considerably larger and more developed in every way, with vastly larger optic and olfactory lobes as well as a much more robust prefrontal region (the portion of the brain devoted to reasoning). We're all aware of T.rex having one of the largest olfactory regions in the fossil record, and how that was the main point championed by Jack Horner in his "T.rex was
exclusively a scavenger" proposition, but take a good and hard look at the eyesight as well. The optic lobe is extremely large and derived, particularly compared to more ancestral optic regions in Carcharodontosaurids, and when combined with the 55 degree overlap in binocular range for the T.rex's stereoscopic vision, the result is the
best eyesight for any known terrestrial animal. T.rex would have had visual acuity 13 times that of our own! To put this in perspective, even the most optically derived extant birds of prey come nowhere even close to the Tyrant Lizard King; eagles are around 4x and falcons 8x that of human vision, and these are the only non-aquatic animals alive today to reach estimates that great. In a study done by Holtz he found that this was "almost certainly" a predatory adaptation, in that a survey conducted of extant fauna concluded modern predators have much better stereoscopic vision than modern scavengers. Take all of these factors and combine them with the fact that T.rex was built to deal more thoroughly encompassing devastation in a single, bone-shattering bite designed to dispatch heavily-built prey items than any other land-based carnivore, and you have, in my personal view, the paragon of terrestrial predators. The best eyesight, smell, cranial weaponry, and an advanced capacity to reason unique among large theropods... still the king.
Can't wait for that maquette.