Contrary to what many posters presume, in real life under load, the higher RPM motor will run less hot due to the higher ratio. The load on the driven pulley is presumed to be a constant in this comparison. Under start-up, the higher rpm motor will reach operating speed more quickly. Under heavy load, the higher rpm motor will maintain a more constant speed. Also, I have observed in real life, that the higher rpm motors do in fact last longer. Most likely because they generate less heat. These are real life observations of commercial equipment that I have installed, serviced and maintained.

I always choose the higher rpm combinations to provide my customers a more dependable piece of equipment.

For a home workshop, I doubt you would notice any cost difference in the electrical consumption.