Do more expensive space heaters actually heat better?

Not really, and reviewers repeatedly point this out. Virtually all corded electric space heaters cap at 1500W, so they produce roughly the same maximum heat output. Across the reviewers and communities we read, the meaningful differences are in noise level, oscillation coverage, thermostat accuracy, safety features and build quality, not raw warming power. A $25 ceramic heater and a $110 tower will both top out at 1500W.