This is the most searched question in the whole subject, and the answers online are mostly personal impressions. Somebody who had four clear nights in Tromso will tell you Tromso is unbeatable. Somebody who had four cloudy ones will tell you the opposite. Both are describing a week of weather.
The comparisons here use things that do not change with whose holiday it was: eleven seasons of cloud statistics, calculated darkness hours, and position relative to the auroral oval.
Choosing a destination
Three ways into the same decision.
Tromso vs Reykjavik vs Rovaniemi
The three compared on geomagnetic latitude, cloud odds and darkness. Tromso sits deepest in the oval, Reykjavik is the most consistent, Rovaniemi has the best single month.
On a budget
The cheapest destination is rarely the one with the cheapest tours. Where the money actually goes, and which economies quietly cost you the trip.
Beyond the classics
Abisko has a mountain range holding the clouds back. Fairbanks and Yellowknife sit deep inside the oval and are considerably colder for it.
The pattern worth knowing before you choose
Coastal destinations are cloudier. Oceans make clouds, and the same Gulf Stream that keeps Tromso unexpectedly mild for 69 degrees north also keeps it overcast. Inland destinations are clearer and colder.
That trade runs through every option on this page. Reykjavik, the most maritime, is the most consistent and never the best. Rovaniemi, the most inland of the three, records the highest single figure we have measured. Abisko, sheltered behind mountains, has a documented local clearing. Fairbanks and Yellowknife are drier and clearer still, at minus thirty.
Clear skies cost you warmth and accessibility. Every destination on this page is a position on that line, and knowing which one you want is more useful than asking which place is best.