Agreed on the reload comments. If you re-load the difference in cost is negligible. Using used brass I can knock out .25-06 with premium Nosler Accubond bullet for $.73/round.
Not sure it's fair to say that there is "no sense in comparing the two." Energy differs by several hundred pounds.
At the end of the day, if your friend likes the .25-06 (and I agree, great cartridge) then I would get setup to produce re-loads to his specs and not look back. Same could be said if he prefers the .243. Pick your favorite and roll your own.