Is it more ethical to hire a tutor to prepare or to cheat on a test?
Measuring the ability to learn tricks (including financial ability) is actually of use to most employers etc., while measuring the ability to cheat is if anything a measure of what employers etc. want to avoid (since typically the risk/reward scheme for them is very different from individuals).

Thus, while having a tutor is not completely fair to those who cannot afford it, it is still a reasonable proxy for desirability.  Cheating is (usually) not.  So it's ethically better than cheating inasmuch as the right people for the positions will tend to be selected for them.