Yeah it takes a few days to get used to the thin air. Add to that a lot of hilly streets and you’ll definitely get winded easily. Even the locals take the hills slower. But the teleferico/cable car system is awesome and very cheap to ride.

Depends where you stay. I was at Hotel Vivenzo which costs about $300 US on a monthly deal including breakfast. Each floor has a repeater and if you get one of the rooms closer to it then you’ll be fine. Also the cafeteria and lounge have good internet.

One place that never seems to be mentioned but should is LaPaz, Bolivia. Beautiful city, relatively cheap, great mountain climate and nice people.