First off, a couple of recommendations on getting there. If you're going to take the Metro, get off at the CIPRO exit, not Ottaviano. The walking distance to the Vatican Museum entrance is about the same, and you do have to go up some stairs, but it's less crowded and you avoid the MASSIVE queue line that blocks off the entire sidewalk, which goes off in the direction of Ottaviano. Or at least come from the West side if at all possible. Second, buy your tickets online at the Vatican's official website www.vatican.va. You'll pay an extra 5 euros per ticket, but you take your voucher right up to the entrance and go inside the building without ANY waiting outside. My wife and I hit security and went up to the ticket booths in less than two minutes. Yes, you only have a ticket VOUCHER, which means you need to exchange your computer printout page for actual tickets (the size of a credit card). And then you feed the tickets through the turnstiles like you're entering the Metro/Subway.
On the other hand, if you don't want to pay the extra fee and intend to wait in line, definitely get off at Ottaviano, as the queue does line up in that direction and will be at a closer distance.
Also keep in mind that the audio guide is rather expensive, at 7 euros. They also don't give you headphones, telling you to hold the unit up to your ear. If you have earphones, bring them. Also, I was able to keep my backpack with me instead of checking it into a cloakroom.
The museum itself was quite extensive, and quite gorgeous. We visited Paris and went to the big museums like D'Orsay and the Louvre. I have to say the Vatican was the easiest to get through, because they organize you to all go in a single direction and snake through the complex. There are a couple of places where you can shortcut to skip things, but otherwise you move from Point A to B to C and don't miss anything all the way through. Most other big museums are a headache because you're going from one wing to the next and constantly backtracking to figure out what you missed. On the other hand, it can be a bit annoying as the place was definitely crowded, and you can only move at the pace of the slowest tour group blocking the way in front of you.
Likewise, the Sistine Chapel itself was a NUTHOUSE. You really are packed in like sardines, as many, MANY people just stop and stare forever. Technically you aren't allowed to take photos, but there were about thirty cameras going off all around me (thankfully, most of them without flash. Most of the museum you're supposed to turn the flash off). After the Sistine, the place really clears up, but there isn't much museum left to see. Once you're finished with the main museum, there are three other smaller galleries you can visit separately within the museums. I strongly recommend the picture gallery. The paintings by Raphael alone make it worth the trip.
Upon exiting, THEN you go DOWN Michelangelo's spiral staircase. There is no access directly through Vatican city, you have to exit and go around. We headed to Saint Peter's Square and Basilica after this, and the walk took about 10-15 minutes. We left around 2pm on a Friday, and here we walked past the queue to get in, finding that it ran most of the length of the wall down Viale Vaticano before it made a right turn.
All in all, great museum. Loved the Egyptian artifacts. Definitely something you should do once in your life.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.