Across from the convention center, near but not on the strip. Good location for business without all the hassles, but if you are there to gamble and "experience" Vegas there are probably better choices. The room, which was really a small suite, was just fine, the staff was very friendly and as a Marriott Rewards member the breakfast buffet (including a custom omelet if you want it) was included in the very reasonable room rate. WiFi is also free for Rewards members, otherwise it's an annoying $10 per day.
It's about a 10-15 minute ride from the airport. I made the mistake of taking one of the shuttle services; they didn't even know where the hotel was! Once I showed them the address they called it the Marriott Suites - which it isn't. Anyway, save yourself the aggravation unless your are really strapped for money and take a cab for the extra $10. You'll get there in 15 minutes instead of over 45 with the waiting for the shuttle to show up and then making stops at other hotels.