Montenegro vs Serbia

Montenegro's $1,181/mo monthly cost (across 2 scored cities); Serbia's $1,156/mo monthly cost (across 2 scored cities) — not enough data to call a winner.

Montenegro's 2.0/5 safety score (across 2 scored cities); Serbia's 2.5/5 safety score (across 2 scored cities) — not enough data to call a winner.

Montenegro's 1.5/5 mobility score (across 2 scored cities); Serbia's 2.1/5 mobility score (across 2 scored cities) — not enough data to call a winner.

Montenegro's 1.2/5 culture score (across 1 scored city); Serbia's 3.2/5 culture score (across 2 scored cities) — not enough data to call a winner.

Montenegro's passport reaches 71 destinations visa-free to Serbia's 91 — Serbia opens more doors without a visa. Passport strength shifts over years of naturalisation, not months of planning, so it's a long-horizon footnote — not scored in the tally.

Serbia is better connected: 8.9M passengers/yr against Montenegro's 3.2M passengers/yr. Montenegro is quieter than 75 of 87 countries worldwide; Serbia is quieter than 65 of 87 countries worldwide. Montenegro sees ~5 air passengers per resident a year; Serbia sees ~1 air passenger per resident a year — a derived figure, not itself ranked.

Montenegro runs -10°C to 33°C for most people; Serbia runs -11°C to 37°C for most people. Depends on you — which range fits your tolerance is the real question here, not a score.