This was one of the best hikes I have gone on in the parks surrounding Las Vegas (including Zion, Grand Canyon and Death Valley). The park brochure describes this hike as "moderate" but it was more strenuous than we had expected near the end - something to keep in mind. There were some scrambling on hands and knees in the last quarter of the hike but I also suspect we had made it more difficult than needed mostly because the trail was not marked and at times it was not clear what was the best way up (especially when there were no one ahead of us for long stretches).
Once you start scaling the rocks to go up, the views looking back down are amazing. But the best view is the one in the end, on top of rocks above the large tank. You can see the entire city in the distance. You will know when you get to the "end" because there is nowhere else to go.
We did this in late December - it took more than 2 hours to the overlook and back (with maybe too many photo stops). In the winter months, I wouldn't get on the trail after 2:30 pm unless you don't plan to go all the way to the end (sunset at around 4:30 pm in late December). You definitely don't want to do this hike in the dark.