I highly recommend going to the West rim. I've seen the South and the West now and the West was unique because: 1) it's on an Indian reservation, so different rules/laws/etc. It's free and open to be viewed all-natural, but that also means there are not a lot of safety barriers, so watch your step! 2) The skywalk is simply amazing!! The views from there are breathtaking and so is the look down the glass floor. They actually only have clear glass in the middle of the walk. On either side, it's frosted, so if someone gets scared, it helps to step onto that.
Recommend that you don't do Hoover dam and West rim in the same day. We split the days which was great, because it allowed more time to enjoy each. When you visit the West rim, don't lose track of time, and when the tour guide tells you to be back, be there! My husband and I were running late getting back and we were the last ones to board the bus, and that was a long walk of shame down the aisle.
Our tour guide was Walter and he was amazing!