In your opinion, which test is more difficult than the other?
Which tests do you want us to compare?
Since your question appears in the SAT/ACT section, I am assuming these are the tests you want to compare.
These two test are very similar. However, the ACT more clearly tests academic skills than the SAT. The ease is in your eyes as a beholder. You could expect to earn somewhat different scores on them, but overall the scores are likely to fall in the same range.
In truth, if one test was dependably easier than the other, that information would be well-known. Several things would have happened. 1) That information would be posted on CC. 2) Students would probably flock to the supposedly easier test. 3) College admissions committees would know which one is easier and would adjust how they would compare scores on the two tests. In fact, that information would probably be provided to them by the two testing companies. 4) ACT and/or SAT would be finding out how the discrepancy happened and would be adjusting their score and metrics to fix the problems.
You could find out which test was a better match for yourself by taking both. At that point, you could compare your scores and send in those scores that are higher.