First off the Tram is free. This particular one has stops for Aria, Bellagio, Monte Carlo and some other one I can't remember. It definitely beats walking and driving and its so quick too. We ended up taking the tram a lot since most of our destinations were at Bellagio and Aria anyways.
There are limited seats and yes the tram does get dirty as the night drags on but once you get past that its not a bad means of transportation at all. I would take it over and over again simply because I got super lazy from walking in the heat. Nowadays you can cut through most hotels and casinos anyways but even then the walking aspect has me feeling blisters.
This is the best resolution for my laziness. Its free, its fast and its convenient. The downer is it doesn't take you to all the hotels but only a few selected ones that connect to it. Still the ones it does take you to are pretty awesome.