The full picture
Heavier users should look at motor power and deck width, not just the weight capacity number. The C2's 220 lb rating is technically possible but leaves no margin — the deck feels narrower and the motor works harder. The A1 Pro handles up to about 200 lb with confidence. The R1 Pro and X21 step up in motor and build quality. The X25 is the only model designed with serious headroom for heavier users.
The Paceora angle
The software story is the same regardless of weight. Paceora improves the daily control flow on any supported model. For heavier users on the X25, it turns a capable treadmill into a more convenient desk companion.