Wow, what a great asset to this city. Came for our first visit to Vegas and knew there is a big difference in maps and actual distance (for walking). Ended up staying at SLS and took the monorail to get to multiple concerts, different tourist activities, and different spots throughout the strip. I bought a 20% discount 3-day pass online and used it to it's full potential (going to explore during the day, coming back in the afternoon, and leaving for entertainment in the evening).
It was clean, never busy, clearly marked where to get on and off, and a map onboard to show you stops and what hotels are by that stop.
Only complaint is not with the monorail, but the hotels. The monorail runs behind hotels and there is poor signage to Las Vegas Blvd so lots of walking around the hotel to find a sign to where to go.