Atomic force microscope cantilevers with integrated piezoresistive displacement sensors are widely used for nanometer-scale topographic measurement and force sensing. Heated cantilevers used in thermomechanical data storage are a promising alternative for topographic measurement. For both cantilever types, this letter models and predicts cantilever displacement sensitivity and noise-limited displacement resolution. The predictions for the thermal cantilever sensitivity compare well with data. Comparing the thermal cantilever with a similarly sized piezoresistive cantilever, the thermal cantilever provides more than one order of magnitude improved performance in both sensitivity and resolution over the piezoresistive cantilever.