[thijsterlouw]

It's extremely busy in the chapel and you will have no time to smell anything. The guards will also try to keep the masses moving along, so there is very little left of the serene atmosphere you expect. That being said, it's still very beautiful.

[prawn]

Beat me to it. Italy is one of the most touristed countries in the world and the Sistine Chapel is one of the most popular spots in the country.

If you have issues with crowded places, be prepared for this one as it is nearly always packed with people. What you'll smell is probably primarily body odour and what you'll hear is yabbering tourists, and guards telling people off for taking photos.

[cpr]

On our family visit to Rome in 2000 (10 people! the logistics! don't remind me ;-), we got a private tour of the Sistine chapel, since my brother knew someone who had pull at the museum. No rush. Fantastico.