To me for a handloader the 35 whelen is the hand downs choice due to the selection of component bullets, parent brass and volume of load data. If you're planning to shoot cast, the 35 bore is IMHO hands down the best caliber due to the huge availability of molds from 90-280 gr.
That said, if you're looking for factory rifles and are planning to hunt internationally where you might need a rifle chambered in a round that you can get factory fodder for in country, the 9.3X62 win's the race.
Either round is an excellent choice for the larger game species.
