Looking for Tourist advice for Grand Canyon

I haven't done either, but think about how you want to see the Canyon:

Helicopter would be a broader area, but all from above (flights below the rim were banned ages ago after too many crashes...).

Mule would be below the rim, but probably not much further than a hike. My only experience with mules was on a Boy Scout hike in Havasupai Canyon (an offshoot of the Grand Canyon), when one of the kids in the troop burned his foot while camping, so a mule had to be rented to get him to the top of the rim (~12 miles or so from the campsite). Even without a burned foot, it didn't look like fun...

But read the other Grand Canyon thread -- I highly recommend driving along the rim to the East entrance. Nice views of the canyon along the way... Then grab lunch at the Cameron Trading Post.

My wife and I took the mules down the canyon many years ago. It was a great experience. I think the minimum trip time for down in the canyon is a full day so you must be talking about something along the rim. It was a great trip, but I could barely walk afterward I was so sore. The leader was a crusty John Wayne type who had been doing it all his life.

I vote for mules!

I'd vote for the mules, too. I worked at the Grand Canyon many (many) years ago both for the concessionaire and then NPS. While the helicopter ride is spectacular, you cannot really witness the grandeur of the canyon until you are in it. iirc, there was a bit of a wait list for the mules, though. Have you checked to see if you can get a reservation?

I vote for hiking on foot.