This thing was canned by everyone under the sun when it opened. So I never tried it....and after having finally done so, I agree. It sucks.
The only thing good about this place is that it's clean, and it can get you to the Las Vegas Hilton (but who wants to go there anyways)?
It's expensive and most importantly - IT DOESN'T GO ANYWHERE COOL! Seriously! The stations are hard to find and hard to get-to behind the eastern side of the Strip's casinos. The rail stops at places like Bally's and Harrah's. We tried to get from the Excalibur to the Wynn, which then included walking to the MGM and from the Harrah's. Sad. Don't waste your time with this terrible nightmare in privately-funded "public" transport.