Below is from one of the blogs about these 3 levels of passes. I would like to climb either the Duomo dome or the Campanile dome. Don't see the need to do both! So debating between the Giotto Pass and the Brunelleschi pass. Does anyone favor one climb over the other? Also I'm hesitating to buy my pass online in advance of my trip. The blog says it's possible to buy the pass onsite. Any idea of how crowded the lines in mid October? Thanks!
Three passes cover the various Duomo sights, each good for three days (establish first day of validity when you purchase). The cathedral itself is free to enter but often has extremely long lines (although with a pass you can use the cathedral's side entrance through the crypt). For everything else, you'll need a pass (and for the Duomo's dome climb, you'll need a reservation, included in the Brunelleschi Pass):
Ghiberti Pass: includes entrance to the cathedral via the crypt (shorter line, near the Campanile), the crypt itself, the Baptistery, and the Duomo Museum.
Giotto Pass: includes everything in the Ghiberti Pass plus the Campanile (bell tower).
Brunelleschi Pass: includes everything in the Giotto Pass, plus a timed entry to climb the Duomo's dome. You'll choose your time slot when you buy the pass.