Quick comparison
Both appeared in 1953. Both have an inline-four engine, mounted at the front. The more powerful one is the Ferrari 625 TF: 223 PS versus 172 PS (converted from kW or hp). The lighter one is the Ferrari 500 Mondial: 720 kg versus 730 kg.
All values come from the data sheets of the two models (sources listed there). The better value is highlighted in green wherever both data sheets give a comparable figure. Photos – Ferrari 500 Mondial: Marco 56, CC BY 2.0; Ferrari 625 TF: François de Dijon, CC BY-SA 4.0. Licenses and originals: Sources & image credits.