I'm also thinking about getting a Smart Trainer, and I've been looking at the Tacx Vortex. Looking on the Tacx website they have some info on the electro brake and there is some kind of graph that supposedly shows the maximum operational range based on speed, power, and simulated gradient. Maybe I'm too stupid, but I cannot figure that thing out. For the Vortex, they claim a max simulated gradient of 7%, but if you look at the graph, the 7% line never intersects the operational area, even at their claim of 75kg max weight. Does someone know how to read and interpret those graphs, because like the OP, I'm concerned about the max gradient and how that may translate to certain course simulations.