1) There is NO DIFFERENCE IN ELECTRIC USAGE, the number of watts will be the same either way and watts and time is what you pay by. Altho the current is halved at 230V the total power is the same.
2) There will be a itty-bitty teeny-tiny performance advantage in the 230V setup because the wiring voltage losses will be less. But in reality we are talking probably less than 1% and you'll never notice the difference.
It really comes down to whats more convenient for you. With a 20A 230V circuit, you could run two high amperage pieces of gear simultaneously on the one circuit (and two outlets) - another possible advantage (e.g. saving one set of wiring). Like a DC and a saw.