We had a bit of an unexpectedly challenging week in Waikaloa due to scheduled tours being cancelled because of the high swell, including our original EKA Canoe Adventure. We were lucky to be able to reschedule it for our last night (it was the only scheduled experience we were actually able to do) and it was SO GREAT and I am so grateful we got to do it. I'd go so far as to say it was one of the most amazing experiences of my life. We saw so many rays, they are so big and came so close (basically grazing our chests), and are so playful with the barrel rolls. We loved it. The crew was also fantastic. Highly recommend.
As some other reviews have said, the boat portion of the trip is quite short...maybe 5-10 minutes, and then you're in the water for probably 30+. You have to hold onto a lit platform with your arms straight and your feet extended and floating on a pool noodle so you don't kick and distract the rays. Our 16 year old, about 10 minutes in, complained that her shoulders hurt, and it does get a teeny bit hard, but it's worth it and she was fine and able to hold on and absolutely loved the experience.
The only other thing I'd add is that we picked EKA bc we wanted to do the canoe, but from what we can tell, many of the boats/groups go to the same spot so you are actually out there with several boats having the same experience so pick whichever boat/group you prefer. The EKA Canoe was cool and the crew was amazing and patient and attentive. Have fun!