I would do both! I've done both as well! A holter monitor is 24 hour monitoring it shows your heart rate all day. A stress test was able to help me when I was 6 years old, it showed that my pacemaker rate dropped below the standard rate.
You have asked an interesting question.
I've had both a holter and stress test multiple times. In my case, the holter was definitive in showing why I needed a pacemaker, it showed a heart beat issue. The stress tests were more influential in leading to stents and eventually, bypass surgery. I'm not sure it's an either/or situation, it's more a matter of evaluating all the information. Hope this helps.
That all depends. Wearing a holter monitor on a lazy sunday may mean it wouldn't see anything wrong. A stress test sees your heart at rest before the test begins, and then when working hard. There is a possibility of course that an event could be missed by both.