It's not so much to do with the type of material that produces the best strength, but rather the process by which the material is cured. In general FDM produces a harder plastic with a better tensile strength and heat resistance. The reason is the laser used in relatively inexpensive SLA printers do not have the capacity or wavelength to cure the resin at similar strength. For this to happen you would require a far more powerful laser that would push the price of your SLA printer up to the $10,000+ range (a bit too pricey for the average hobbyist).