Booked this through concierge at my hotel, and am so glad I did! Amazing experience, so much fun! I went by myself, and was told in advance that they might have to send me up with someone else, depending on conditions. I was absolutely fine with that - figured I'd be able to convince someone to go up again for free!
Two people in my group did not speak English, but the instructor was fluent in their language, and was able to communicate easily with everyone, so that we all knew what to expect. Incredible views, friendly and FUN instructors/boat captains, and an all-around good time.
So why only 4 stars instead of 5?
The lady who greeted me at the front desk was not very friendly. She seemed irritated, like my presence was preventing her from beating the next level of Candy Crush or something. First impressions are important, and if I hadn't already made the booking through the hotel, and just been looking to book when I walked in, I likely wouldn't have booked based on my interaction with her.