I booked a tour through Viator.com. The experience was exactly as advertised, and really awesome. I loved as we decended into the canyon, landing on a scenic turning point, with a champagne lunch nonetheless. We flew right over Vegas coming back, and I wished it had been at night rather than day.
Only thing I didn't like....it was me (solo traveler), and a couple and a set of parents with a child. Add that up, and its 6 seats per helicopter. (2 in the front, 4 in the back.) Naturally, I sat in the back at a window on the way out. The couple got to sit in front going out. Then, the other 3some took the front, as well as a window seat. In case you're not following, I got a back window seat going out, and a middle back seat coming back to Vegas. For $300, I should've had the opportunity to sit in front. It wasn't even discussed; it was like, I'm by myself, and the couples deserve to experience it before me. Which sucked. Which is why you're getting 4 stars. Other than that, I felt safe, and it was pretty fun.